Several web server virtual machines in your environment are experiencing poor performance.
Upon further investigation you learn that one very active database virtual machine is consuming
most of your storage bandwidth. You would like to restrict the storage performance of the
database VM to increase the performance of the web server VMs. Which of the following features
will help you do this?

A.
Distributed Resource Scheduler (DRS)

B.
Storage I/O Control

C.
vMotion

D.
Storage vMotion

Explanation:
http://searchvmware.techtarget.com/definition/VMware-DRS