Which of the following approaches provides the lowest c…

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