This DOP-C02 practice question tests your understanding of sdlc automation. The scenario asks you to isolate a root cause — eliminate options that address a different problem before choosing. 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.
Refer to the exhibit. An AWS CloudFormation template includes a Lambda function with the ARN shown. The function is part of a custom resource to create an S3 bucket. The stack creation fails with the error 'Function not found: arn:aws:lambda:us-east-1:123456789012:function:my-function'. The Lambda function exists in the same account and region. What is the most likely cause?
Clue words in this question
Noticing these words before you look at the options changes how you read each choice.
Clue: "most likely"
Why it matters: Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The Lambda function is defined in the same template and has a circular dependency
The most likely cause is a circular dependency (Option A). In AWS CloudFormation, when a Lambda function is defined in the same template as a custom resource that invokes it, the function must be fully created and available before the custom resource can be processed. If the Lambda function depends on the S3 bucket (e.g., via a bucket name or property), and the custom resource also depends on the Lambda function, CloudFormation cannot resolve the order of creation, leading to a 'Function not found' error because the function hasn't been created yet when the custom resource attempts to invoke it.
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.
✓
The Lambda function is defined in the same template and has a circular dependency
Why this is correct
CloudFormation cannot use a resource that is being created in the same stack as a custom resource without proper DependsOn
Clue confirmation
The clue word "most likely" in the question point toward this answer.
Related concept
Read the scenario before looking for a memorised answer.
✗
The Lambda function is not in the same AWS region
Why it's wrong here
The ARN shows us-east-1, same as the stack
✗
The Lambda function lacks necessary IAM permissions
Why it's wrong here
Permissions issue would show an access denied error
✗
The Lambda function ARN is malformed
Why it's wrong here
The ARN appears correctly formatted
Common exam traps
Common exam trap: answer the scenario, not the keyword
The trap here is that candidates often assume the error is due to a missing function or region mismatch, but the real issue is a circular dependency in the CloudFormation template that prevents the Lambda function from being created before the custom resource tries to invoke it.
Trap categories for this question
Command / output trap
The ARN shows us-east-1, same as the stack
Detailed technical explanation
How to think about this question
CloudFormation custom resources rely on a Lambda function to handle create, update, and delete operations. When the Lambda function is defined in the same template, CloudFormation uses a 'DependsOn' attribute implicitly or explicitly to order resource creation. If a circular dependency exists (e.g., the Lambda function references the S3 bucket's physical ID, and the custom resource references the Lambda function), CloudFormation's dependency graph cannot be resolved, and it may attempt to invoke the function before it exists, resulting in a 'Function not found' error. This is a common pitfall in infrastructure-as-code design where resource interdependencies are not carefully mapped.
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 media company stores terabytes of video archives that are accessed once a year for audit purposes. Moving these objects to a cold storage tier (Azure Archive, S3 Glacier, or Google Nearline) costs a fraction of hot storage. Questions like this test whether you understand storage tiers, access frequency tradeoffs, and retrieval latency requirements.
Visual reference
Quick reference
AWS S3 Storage Class Comparison
Storage Class
Min Duration
Retrieval
Use Case
S3 Standard
None
Immediate
Frequently accessed data
S3 Standard-IA
30 days
Immediate
Infrequent access, rapid retrieval
S3 One Zone-IA
30 days
Immediate
Non-critical infrequent data
S3 Intelligent-Tiering
None
Immediate–hours
Unknown or changing access patterns
S3 Glacier Instant
90 days
Milliseconds
Archive with instant retrieval
S3 Glacier Flexible
90 days
Minutes–hours
Archive, flexible retrieval
S3 Glacier Deep Archive
180 days
Hours
Long-term compliance archive
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.
SDLC Automation — This question tests SDLC Automation — Read the scenario before looking for a memorised answer..
What is the correct answer to this question?
The correct answer is: The Lambda function is defined in the same template and has a circular dependency — The most likely cause is a circular dependency (Option A). In AWS CloudFormation, when a Lambda function is defined in the same template as a custom resource that invokes it, the function must be fully created and available before the custom resource can be processed. If the Lambda function depends on the S3 bucket (e.g., via a bucket name or property), and the custom resource also depends on the Lambda function, CloudFormation cannot resolve the order of creation, leading to a 'Function not found' error because the function hasn't been created yet when the custom resource attempts to invoke it.
What should I do if I get this DOP-C02 question wrong?
Identify which exam domain this question belongs to, review the core concept, then practise similar questions from the same domain.
Are there clue words in this question I should notice?
Yes — watch for: "most likely". Probability qualifier — the question wants the most probable cause or outcome, not a guaranteed one. Eliminate low-probability options.
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 →
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
This DOP-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 DOP-C02 exam.
Question Discussion
Share a tip, memory trick, or ask about the reasoning behind this question. Do not post real exam questions, leaked content, braindumps, or copyrighted exam material. Comments are moderated and may be removed without notice.
Sign in to join the discussion.