- A
Amazon EC2 with Auto Scaling
Why wrong: Amazon EC2 with Auto Scaling requires provisioning and managing virtual servers. Scaling is based on metrics like CPU utilization, not per individual request. Even when idle, running instances incur charges. This does not meet the need for fully managed, per-request scaling and pay-per-use billing.
- B
AWS Lambda
AWS Lambda is a serverless compute service that executes code in response to events. It automatically scales to handle any volume of requests, charging only for the compute time consumed during execution (per millisecond). No servers to provision or manage, making it ideal for unpredictable, short-lived workloads.
- C
Amazon ECS with Fargate launch type
Why wrong: Amazon ECS with Fargate provides serverless container orchestration, but it still requires defining container images and task definitions. It charges for running tasks even when they are idle, and scaling is not as fine-grained per individual request. It is less cost-effective and simpler than Lambda for very short, bursty operations.
- D
Amazon Lightsail
Why wrong: Amazon Lightsail offers preconfigured virtual private servers at a fixed monthly price. It does not automatically scale with request volume, and billing is not based on actual compute time used. It is not suitable for a highly variable, pay-per-use workload.
Quick Answer
The answer is AWS Lambda. This fully managed compute service is the correct choice because it automatically scales from zero to thousands of concurrent executions in response to unpredictable bursty workloads, such as flash sales that spike to thousands of requests per second after long idle periods. Lambda executes code only when triggered by HTTPS events, charges solely for the compute time consumed in 1ms increments, and requires no server provisioning or infrastructure management, making it ideal for short-lived operations like data validation and database writes. On the AWS Certified Cloud Practitioner CLF-C02 exam, this scenario tests your understanding of serverless compute versus container-based or instance-based services; a common trap is choosing Amazon ECS or EC2 Auto Scaling, which still involve server management and idle costs. Remember the memory tip: Lambda is for “little bursts” of work that “lamb” up instantly and cost nothing when idle.
CLF-C02 Cloud Technology and Services Practice Question
This CLF-C02 practice question tests your understanding of cloud technology and services. Match the stated requirement to the specific cloud service, access model, or configuration option — many options are valid in isolation but not for this scenario. After answering, compare your reasoning against the explanation and wrong-answer breakdown below. Once you have made your selection, read the full explanation to reinforce the concept and understand why each distractor is designed to mislead on exam day.
A company is developing a REST API that processes customer orders. The API receives JSON payloads via HTTPS and performs short-lived operations, such as data validation, transformation, and writing to a database. The workload is very unpredictable: sometimes there are long periods of inactivity, but during flash sales the API may receive thousands of requests per second for a few minutes. The company wants a fully managed compute service that automatically scales to handle any request volume, charges only for the compute time used during execution, and requires no server provisioning or ongoing infrastructure management. Which AWS service should the company use?
Answer choices
Why each option matters
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
AWS Lambda
AWS Lambda is the correct choice because it is a fully managed, event-driven compute service that automatically scales from zero to thousands of concurrent executions in response to incoming HTTPS requests. It charges only for the compute time consumed during execution (in 1ms increments), requires no server provisioning, and is ideal for short-lived operations like data validation, transformation, and database writes. The unpredictable, bursty workload pattern—long idle periods followed by flash sales—maps perfectly to Lambda's pay-per-use model and automatic scaling.
Key principle: Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
- ✗
Amazon EC2 with Auto Scaling
Why it's wrong here
Amazon EC2 with Auto Scaling requires provisioning and managing virtual servers. Scaling is based on metrics like CPU utilization, not per individual request. Even when idle, running instances incur charges. This does not meet the need for fully managed, per-request scaling and pay-per-use billing.
- ✓
AWS Lambda
Why this is correct
AWS Lambda is a serverless compute service that executes code in response to events. It automatically scales to handle any volume of requests, charging only for the compute time consumed during execution (per millisecond). No servers to provision or manage, making it ideal for unpredictable, short-lived workloads.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
Amazon ECS with Fargate launch type
Why it's wrong here
Amazon ECS with Fargate provides serverless container orchestration, but it still requires defining container images and task definitions. It charges for running tasks even when they are idle, and scaling is not as fine-grained per individual request. It is less cost-effective and simpler than Lambda for very short, bursty operations.
- ✗
Amazon Lightsail
Why it's wrong here
Amazon Lightsail offers preconfigured virtual private servers at a fixed monthly price. It does not automatically scale with request volume, and billing is not based on actual compute time used. It is not suitable for a highly variable, pay-per-use workload.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse 'fully managed' with 'container orchestration' and select ECS with Fargate, overlooking that Lambda is the only option that charges strictly per execution (not per provisioned resource) and automatically scales to zero during inactivity without any ongoing cost.
Detailed technical explanation
How to think about this question
AWS Lambda integrates natively with API Gateway to expose REST APIs, automatically scaling each function invocation as a separate execution environment. Under the hood, Lambda uses a pool of pre-warmed sandboxes to reduce cold start latency, but during extreme bursts, new sandboxes are created on demand, which can introduce a few hundred milliseconds of cold start time—this is acceptable for the described short-lived operations. The service enforces a maximum execution timeout of 15 minutes, making it unsuitable for long-running processes, but perfect for the sub-second validation and database writes in this scenario.
KKey Concepts to Remember
- Read the scenario before looking for a memorised answer.
- Find the constraint that changes the correct option.
- Eliminate answers that are true in general but not in this case.
TExam Day Tips
- Watch for words such as best, first, most likely and least administrative effort.
- Review why wrong options are wrong, not only why the correct option is correct.
Key takeaway
Answer the scenario, not the keyword: identify the specific constraint before choosing the most familiar-sounding option.
Real-world example
How this comes up in practice
An e-commerce site experiences heavy traffic on Black Friday and near-zero traffic during off-peak weeks. Rather than provisioning permanent large VMs, the team uses auto-scaling groups that add capacity automatically under load and reduce it overnight. Questions like this test whether you understand elasticity, availability zones, and cloud compute scaling patterns.
What to study next
Got this wrong? Here's your next step.
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FAQ
Questions learners often ask
What does this CLF-C02 question test?
Cloud Technology and Services — This question tests Cloud Technology and Services — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: AWS Lambda — AWS Lambda is the correct choice because it is a fully managed, event-driven compute service that automatically scales from zero to thousands of concurrent executions in response to incoming HTTPS requests. It charges only for the compute time consumed during execution (in 1ms increments), requires no server provisioning, and is ideal for short-lived operations like data validation, transformation, and database writes. The unpredictable, bursty workload pattern—long idle periods followed by flash sales—maps perfectly to Lambda's pay-per-use model and automatic scaling.
What should I do if I get this CLF-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
What is the key concept behind this question?
Read the scenario before looking for a memorised answer.
About these practice questions
Courseiva creates original exam-style practice questions with explanations and wrong-answer analysis. It does not publish real exam questions, exam dumps, or protected exam content. Learn why practice questions differ from exam dumps →
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Last reviewed: Jun 11, 2026
This CLF-C02 practice question is part of Courseiva's free Amazon Web Services certification practice question bank. Courseiva provides original exam-style practice questions with explanations, topic-based practice, mock exams, readiness tracking, and study analytics to help learners prepare for the CLF-C02 exam.
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