The correct combination is using S3 server-side encryption and enabling SageMaker inter-container traffic encryption. This works because S3 SSE-S3 or SSE-KMS encrypts the training data at rest in the bucket, while SageMaker’s inter-container traffic encryption enforces HTTPS between training instances, securing the data in transit. On the AWS Certified Machine Learning Specialty MLS-C01 exam, this question tests your understanding of the shared responsibility model and the specific encryption controls available within SageMaker—a common trap is assuming that a single measure, like SSL or VPC isolation, covers both states. Remember that encrypting PII at rest and in transit for SageMaker training requires two distinct actions: one for storage and one for network traffic. A helpful memory tip is “S3 for storage, HTTPS for flow”—if you see an option missing either, it’s automatically wrong.
MLS-C01 Practice Question: Machine Learning Implementation and Operations
This MLS-C01 practice question tests your understanding of machine learning implementation and operations. 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 using SageMaker to train a model. The training data includes personally identifiable information (PII). The company must ensure that the data is encrypted at rest and in transit. Which combination of actions meets these requirements?
Answer the question above first, then reveal the full breakdown to understand why each option is right or wrong.
Correct answer & explanation
✓
Use S3 server-side encryption and enable SageMaker inter-container traffic encryption
Option C is correct: S3 SSE-S3 or SSE-KMS encrypts data at rest, and SageMaker uses HTTPS for in-transit encryption. Option A (only SSL) lacks at-rest encryption. Option B (only S3 SSE) lacks in-transit. Option D (VPC only) does not encrypt.
Key principle: Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
Answer analysis
Option-by-option breakdown
For each option: why learners choose it and why it is or isn't the right answer here.
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Use S3 server-side encryption with S3 managed keys (SSE-S3)
Common exam trap: usable hosts are not the same as total addresses
Subnetting questions often tempt you into counting all addresses. In normal IPv4 subnets, the network and broadcast addresses are not usable host addresses.
Detailed technical explanation
How to think about this question
Subnetting questions test whether you can identify the network, broadcast address, usable range, mask and correct subnet. Slow down enough to calculate the block size correctly.
KKey Concepts to Remember
CIDR notation defines the prefix length.
Block size helps identify subnet boundaries.
Network and broadcast addresses are not usable hosts in normal IPv4 subnets.
The required host count determines the smallest suitable subnet.
TExam Day Tips
→Write the block size before choosing the subnet.
→Check whether the question asks for hosts, subnets or a specific address range.
→Do not confuse /24, /25, /26 and /27 host counts.
Key takeaway
Count usable hosts — not total addresses — and remember that the network and broadcast addresses are not available to hosts in standard IPv4 subnets.
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.
What to study next
Got this wrong? Here's your next step.
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related MLS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
Machine Learning Implementation and Operations — This question tests Machine Learning Implementation and Operations — CIDR notation defines the prefix length..
What is the correct answer to this question?
The correct answer is: Use S3 server-side encryption and enable SageMaker inter-container traffic encryption — Option C is correct: S3 SSE-S3 or SSE-KMS encrypts data at rest, and SageMaker uses HTTPS for in-transit encryption. Option A (only SSL) lacks at-rest encryption. Option B (only S3 SSE) lacks in-transit. Option D (VPC only) does not encrypt.
What should I do if I get this MLS-C01 question wrong?
Review block sizes, usable host formulas (2^n − 2), and how to find network and broadcast addresses for /24 through /30. Then practise related MLS-C01 subnetting questions on CIDR, address ranges, and subnet selection.
What is the key concept behind this question?
CIDR notation defines the prefix length.
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This MLS-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 MLS-C01 exam.
Question Discussion
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