The correct answer is that the Deny statement explicitly denies deletion of any instance with an identifier starting with 'prod-', and in AWS IAM policy evaluation, a Deny always overrides any Allow. This is the core principle of explicit deny precedence: even if another statement grants permission to delete RDS instances, a matching Deny statement will block the action and return an AccessDenied error. On the AWS Certified Database Specialty DBS-C01 exam, this concept frequently appears in questions testing your understanding of IAM policy evaluation logic, often as a trap where you might focus on missing actions or incorrect ARNs instead of recognizing the overriding Deny. A common memory tip is "Deny is the final word" — think of it as a hard block that no Allow can bypass, so always check for explicit Deny statements first when troubleshooting access issues.
DBS-C01 Deployment and Migration Practice Question
This DBS-C01 practice question tests your understanding of deployment and migration. 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.
Refer to the exhibit. A database administrator has this IAM policy attached to their user. They attempt to delete the database instance 'prod-mydb' but receive an 'AccessDenied' error. Why?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
The Deny statement explicitly denies deletion of any instance with an identifier starting with 'prod-'.
Option C is correct because the Deny statement explicitly denies deletion of any DB instance with identifier starting with 'prod-', and Deny takes precedence over Allow. Option A is wrong because the policy allows deletion for non-prod instances. Option B is wrong because the resource ARN is correct for prod-mydb. Option D is wrong because the error is not due to missing DescribeDBInstances.
Key principle: ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
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 policy does not allow the rds:DeleteDBInstance action for any resource.
Why it's wrong here
The policy allows DeleteDBInstance on all resources, but then denies it for prod-*.
✗
The resource ARN in the Deny statement does not match the instance.
Why it's wrong here
The ARN matches: db:prod-* covers prod-mydb.
✗
The user does not have permission to describe the DB instance.
Why it's wrong here
The user has DescribeDBInstances permission.
✓
The Deny statement explicitly denies deletion of any instance with an identifier starting with 'prod-'.
Why this is correct
The Deny statement overrides the Allow, preventing deletion of prod instances.
Related concept
Standard ACLs match source addresses.
Common exam traps
Common exam trap: ACLs stop at the first match
ACLs are processed top to bottom. The first matching entry wins, and an implicit deny usually exists at the end.
Detailed technical explanation
How to think about this question
ACL questions test precision: source, destination, protocol, port and direction. A generally correct ACL can still fail if it is applied on the wrong interface or in the wrong direction.
KKey Concepts to Remember
Standard ACLs match source addresses.
Extended ACLs can match source, destination, protocol and ports.
The first matching ACL entry is used.
There is usually an implicit deny at the end.
TExam Day Tips
→Check inbound versus outbound direction.
→Read the ACL from top to bottom.
→Look for a broader permit or deny above the intended line.
Key takeaway
ACLs process entries top to bottom and stop at the first match. Entry order and interface direction matter as much as the permit or deny statement.
Real-world example
How this comes up in practice
A company's IT admin needs to give a contractor read-only access to production logs without sharing account credentials. Using role-based access control (RBAC) and temporary scoped permissions — not a permanent shared password — is the correct pattern. Questions like this test whether you can apply least-privilege access across cloud identity services.
What to study next
Got this wrong? Here's your next step.
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
Deployment and Migration — This question tests Deployment and Migration — Standard ACLs match source addresses..
What is the correct answer to this question?
The correct answer is: The Deny statement explicitly denies deletion of any instance with an identifier starting with 'prod-'. — Option C is correct because the Deny statement explicitly denies deletion of any DB instance with identifier starting with 'prod-', and Deny takes precedence over Allow. Option A is wrong because the policy allows deletion for non-prod instances. Option B is wrong because the resource ARN is correct for prod-mydb. Option D is wrong because the error is not due to missing DescribeDBInstances.
What should I do if I get this DBS-C01 question wrong?
Review ACL processing order, placement rules (standard near destination, extended near source), and inbound vs outbound direction. Study wildcard masks and implicit deny. Then practise related DBS-C01 ACL questions on filtering logic and placement.
What is the key concept behind this question?
Standard ACLs match source addresses.
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 →
These questions test the same concept from different angles. Work through them to make sure you can recognise it however the exam phrases it.
Variation 1. A database administrator is trying to delete the RDS instance named 'prod-critical' using the AWS CLI. The IAM policy shown is attached to the user. What will happen?
hard
A.The delete will succeed only if the user includes a condition.
✓ B.The delete will fail because the Deny statement explicitly denies the action for that resource.
C.The delete will fail because the policy has a syntax error.
D.The delete will succeed because the Allow statement grants permission.
Why B: Option A is correct because the Deny statement explicitly denies the delete action for that specific resource, and Deny always overrides Allow. Option B is wrong because the Allow does not apply to the specific resource due to the Deny. Option C is wrong because the Deny is explicit. Option D is wrong because the Deny is on the action, not condition.
Last reviewed: Jun 20, 2026
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This DBS-C01 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 DBS-C01 exam.
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