- A
Amazon EC2 Reserved Instances
Why wrong: Reserved Instances are a billing option that provides discounts in exchange for a usage commitment. They do not automatically adjust the number of running instances.
- B
AWS Elastic Load Balancing
Why wrong: Elastic Load Balancing distributes traffic across instances but does not automatically adjust the number of instances. ELB works alongside Auto Scaling Groups.
- C
Amazon EC2 Auto Scaling
EC2 Auto Scaling Groups automatically launch or terminate instances based on scaling policies. Scheduled policies add capacity before known peaks; dynamic policies respond to CloudWatch metrics in real time.
- D
AWS CloudFormation
Why wrong: CloudFormation provisions infrastructure as code. While it can define the Auto Scaling group, CloudFormation itself does not dynamically adjust running instance counts based on demand.
Quick Answer
Amazon EC2 Auto Scaling is the correct choice because it automatically adjusts the number of EC2 instances based on demand, adding capacity during traffic spikes and removing it during quiet periods. This service uses scaling policies—such as scheduled scaling for predictable weekday morning rushes or dynamic scaling for real-time load changes—to match the exact pattern described, where employees cause peak usage each morning and off-hours see very few active users. On the AWS Certified Cloud Practitioner CLF-C02 exam, this question tests your understanding of how Auto Scaling operationalizes elasticity without manual intervention; a common trap is confusing it with Elastic Load Balancing, which distributes traffic but does not change instance count. Remember the memory tip: “Auto Scaling = automatic sizing” to instantly recall that it handles adding and removing EC2 instances based on demand, making it the perfect fit for variable workloads like daily traffic spikes.
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's application experiences traffic spikes every weekday morning when employees arrive at work. During off-hours, very few users are active. Which AWS feature automatically adjusts the number of EC2 instances based on demand, adding instances during peak hours and removing them during quiet periods?
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
Amazon EC2 Auto Scaling
Amazon EC2 Auto Scaling is the correct service because it automatically adjusts the number of EC2 instances in response to demand, using scaling policies (e.g., scheduled scaling or dynamic scaling) to add instances during peak hours and terminate them during quiet periods. This directly matches the described traffic pattern of weekday morning spikes and off-hour lulls, without manual intervention.
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 Reserved Instances
Why it's wrong here
Reserved Instances are a billing option that provides discounts in exchange for a usage commitment. They do not automatically adjust the number of running instances.
- ✗
AWS Elastic Load Balancing
Why it's wrong here
Elastic Load Balancing distributes traffic across instances but does not automatically adjust the number of instances. ELB works alongside Auto Scaling Groups.
- ✓
Amazon EC2 Auto Scaling
Why this is correct
EC2 Auto Scaling Groups automatically launch or terminate instances based on scaling policies. Scheduled policies add capacity before known peaks; dynamic policies respond to CloudWatch metrics in real time.
Related concept
Read the scenario before looking for a memorised answer.
- ✗
AWS CloudFormation
Why it's wrong here
CloudFormation provisions infrastructure as code. While it can define the Auto Scaling group, CloudFormation itself does not dynamically adjust running instance counts based on demand.
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often confuse Elastic Load Balancing with Auto Scaling, assuming load balancers automatically scale instances, when in fact ELB only distributes traffic and requires Auto Scaling to adjust capacity.
Detailed technical explanation
How to think about this question
Under the hood, EC2 Auto Scaling uses a launch template or configuration to define instance specifications, and scaling policies can be based on CloudWatch metrics (e.g., CPU utilization) or scheduled actions (e.g., cron-like expressions for predictable spikes). A subtle behavior is that Auto Scaling maintains a minimum and maximum instance count, and during scale-in, it uses termination policies (e.g., oldest launch template, closest to next billing hour) to decide which instances to terminate, which can impact cost and availability if not configured carefully.
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
A startup's cloud architect reviews their monthly bill and notices costs are higher than expected for a long-running batch job. Switching from on-demand instances to Reserved Instances — or using Spot/Preemptible VMs — can reduce compute costs by up to 72 %. Questions like this test whether you understand the tradeoffs between commitment, flexibility, and cost across cloud pricing models.
What to study next
Got this wrong? Here's your next step.
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
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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: Amazon EC2 Auto Scaling — Amazon EC2 Auto Scaling is the correct service because it automatically adjusts the number of EC2 instances in response to demand, using scaling policies (e.g., scheduled scaling or dynamic scaling) to add instances during peak hours and terminate them during quiet periods. This directly matches the described traffic pattern of weekday morning spikes and off-hour lulls, without manual intervention.
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.
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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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