In regard to DynamoDB, for which one of the following parameters does Amazon not charge you?

A.
Cost per provisioned write units

B.
Cost per provisioned read units

C.
Storage cost

D.
I/O usage within the same Region

Explanation:
In DynamoDB, you will be charged for the storage and the throughput you use rather than for the I/O which has been
used.
http://aws.amazon.com/dynamodb/pricing/