Which of the following approaches provides the lowest cost for Amazon Elastic Block Store
snapshots while giving you the ability to fully restore data?

A.
Maintain two snapshots: the original snapshot and the latest incremental snapshot.

B.
Maintain a volume snapshot; subsequent snapshots will overwrite one another

C.
Maintain a single snapshot the latest snapshot is both Incremental and complete.

D.
Maintain the most current snapshot, archive the original and incremental to Amazon Glacier.

Explanation:
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/ebs-deleting-snapshot.html