A user has created a snapshot of an EBS volume. Which of the below mentioned usage cases is not possible with respect
to a snapshot?

A.
Mirroring the volume from one AZ to another AZ

B.
Launch an instance

C.
Decrease the volume size

D.
Increase the size of the volume

Explanation:
The EBS snapshots are a point in time backup of the volume. It is helpful to move the volume from one AZ to another or
launch a new instance. The user can increase the size of the volume but cannot decrease it less than the original snapshot
size.
http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/EBSSnapshots.html