Which AWS service or storage class will meet these requirements MOST cost-effectively?

Explanations:

Amazon FSx for Lustre is designed for high-performance file systems and is not optimized for infrequent access or long-term storage, making it more expensive for data archiving.

Amazon Elastic Block Store (EBS) is primarily used for block storage with low-latency access for EC2 instances, not ideal for long-term archiving or infrequent access due to higher costs.

Amazon Elastic File System (EFS) is suitable for file storage but is designed for applications that require frequent access, resulting in higher costs compared to other storage options for infrequent data.

Amazon S3 Glacier Flexible Retrieval is specifically designed for long-term data archiving and infrequently accessed data, offering a cost-effective solution for storage with lower retrieval costs compared to the other options.