How should the thumbnail images be stored to ensure the LOWEST cost?

A photo-sharing website running on AWS allows users to generate thumbnail images of photos stored in Amazon S3. An Amazon DynamoDB table maintains the locations of photos, and thumbnails are easily re-created from the originals if they are accidentally deleted.

How should the thumbnail images be stored to ensure the LOWEST cost?
A . Amazon S3 Standard-Infrequent Access (S3 Standard-IA) with cross-region replication
B . Amazon S3
C . Amazon Glacier
D . Amazon S3 with cross-region replication

Answer: B