You run a clustered NoSQL database on AWS EC2 using AWS EBS. You need to reduce latency for database response times. Performance is the most important concern, not availability. You did not perform the initial setup, someone without much AWS knowledge did, so you are not sure if they configured everything optimally. Which of the following is NOT likely to be an issue contributing to increased latency?

http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/placement-groups.html

A.
The EC2 instances are not EBS Optimized.

B.
The database and requesting system are both in the wrong Availability Zone.

C.
The EBS Volumes are not using PIOPS.

D.
The database is not running in a placement group.

Explanation:
Explanation/Reference:
For the highest possible performance, all instances in a clustered database like this one should be in a single Availability
Zone in a placement group, using EBS optimized instances, and using PIOPS SSD EBS Volumes. The particular
Availability Zone the system is running in should not be important, as long as it is the same as the requesting resources.