The workload described is event-driven, low volume, and sporadic, making serverless architecture the most cost-effective choice. AWS Lambda, when triggered by S3 event notifications, runs only when new photos are uploaded and incurs cost only for execution time.
Option C uses S3 event notifications to invoke a Lambda function whenever a new object is created. The Lambda function generates a thumbnail and uploads it to a second S3 bucket. This solution requires no servers, no scheduling, and no idle compute costs, making it extremely cost-efficient for 150 uploads per day.
Options A and B involve running long-lived compute resources that would remain idle most of the time, resulting in unnecessary cost. Option D is invalid because S3 Storage Lens is designed for storage analytics and reporting, not event-driven processing.
Therefore, C is the most cost-effective and operationally efficient solution.

The correct solution is to create anIAM roleand attach it to the EC2 instance profile. AWS documentation states that applications running on EC2 should use IAM roles so the instance can receivetemporary credentials automaticallythrough the instance metadata service. This avoids embedding long-term access keys in code or on the server. DynamoDB supports IAM and temporary credentials, so the application can use the role's permissions to access the table securely. EC2 key pairs are only for SSH access and have nothing to do with DynamoDB authorization. IAM users and long-term access keys are less secure and create unnecessary credential management overhead.

Option A is the most operationally efficient because it moves permissions from individual users todepartment- based IAM groups, which is easier to manage consistently at scale. AWS IAM best practices emphasize applyingleast privilegeand note that managed policies can help get started, though broad managed policies like AdministratorAccess are not least privilege in the strictest sense. Given the answer choices, placing engineering and operations users into separate groups with the appropriate policies and removing direct user- level permissions is the cleanest and most maintainable improvement. Options C and D still leave user-by- user administration, and option B is clearly over-permissive.

AWS Glue Crawler: AWS Glue is a fully managed ETL (Extract, Transform, Load) service that makes it easy to prepare and load data for analytics. A Glue crawler can automatically discover new data and schema in Amazon S3, making it easy to keep the data catalog up-to-date.
Crawling the Data:
Set up an AWS Glue crawler to scan the S3 bucket containing the clickstream data.
The crawler will automatically detect the schema and create/update the tables in the AWS Glue Data Catalog.
Amazon Athena:
Athena is an interactive query service that makes it easy to analyze data in Amazon S3 using standard SQL.
Once the data catalog is updated by the Glue crawler, use Athena to query the clickstream data directly in S3.
Operational Efficiency: This solution leverages fully managed services, reducing operational overhead. Glue crawlers automate data cataloging, and Athena provides a serverless, pay-per-query model for quick data analysis without the need to set up or manage infrastructure.
References:
AWS Glue
Amazon Athena

Comprehensive and Detailed Step-by-Step Explanation:
The requirement is toprevent data deletion by any user, including administrators, for 7 years while allowing automatic deletion afterward.
S3 Object Lock in Compliance Mode (Correct Choice - C)
Compliance mode ensures that even the root user cannot delete or modify the objects during the retention period.
After 7 years, the S3 Lifecycle policy automatically deletes the objects.
This meets bothimmutability and automatic deletionrequirements.
Governance Mode (Option B - Incorrect)
Governance mode prevents deletion,but administrators can override it.
The requirement explicitly states thateven administrators must not be able to delete the data.
S3 Bucket Policy (Option A - Incorrect)
An S3 bucket policy candeny deletes, but policies can be modified at any time by administrators.
It does not enforce strict retention like Object Lock.
S3 Batch Operations Job (Option D - Incorrect)
A legal hold does not have an automatic expiration.
Legal holds must be manually removed, which is not efficient.
Why Option C is Correct:
S3 Object Lock in Compliance Mode prevents deletion by all users, including administrators.
The S3 Lifecycle policy deletes the data automatically after 7 years, reducing operational overhead.
References:
S3 Object Lock Compliance Mode
S3 Lifecycle Policies