Which memory conservation technique collaborates with the server to reclaim pages that are
redundant in a virtual machine or virtual machines?

A.
Memory Balloon Driver

B.
Transparent Page Sharing

C.
Redundant Memory Driver

D.
VMkernel Swap

Explanation:
http://pubs.vmware.com/vsphere-50/topic/com.vmware.ICbase/PDF/vsphere-esxivcenter-server-50-resource-management-guide.pdf