The correct answer is: Use Amazon S3.

Amazon S3 is highly durable, scalable, and cost-effective for storing long-term data. It supports concurrent access to objects by multiple systems, making it ideal for analytics workloads. With features like S3 Lifecycle policies, the company can move older logs to more cost-efficient storage classes (e.g., S3 Glacier or Glacier Deep Archive) while keeping newer logs readily accessible. This allows them to meet both the 7-year retention requirement and the concurrent access needs at the lowest cost.

Why the other options are incorrect:

Amazon EBS is block storage meant for individual EC2 instances. It does not natively support access from multiple instances and becomes expensive at scale for long-term storage.

Amazon EFS is a shared file system for Linux workloads and does support concurrent access, but it is significantly more expensive than S3especially for infrequently accessed archival data. It is better suited for active, low-latency file access.

Amazon EC2 instance store is ephemeral. Data is lost when the instance is stopped or terminated, which makes it unsuitable for durable, long-term storage or compliance use cases.

Why this question is important: It tests your knowledge of AWS storage types and how to select the most appropriate and economical option based on durability, access patterns, and retention requirements.

Tip: When you see a long-term retention requirement combined with concurrent access needs, think of Amazon S3 with lifecycle policies. It's often the best fit for compliance and analytical workloads.

Full AWS Practitioner Certification Question