Before you begin the rollout of your private cloud, the technical project leader wants to ensure you
have the vSphere components required by vCloud Director in place first. Which two vSphere
components are required by vCloud? (Choose two.)

A.
ESXi hypervisor

B.
vCenter Server

C.
vSphere Data Protection

D.
vCenter Orchestrator

Explanation:
http://pubs.vmware.com/vcd-51/index.jsp?topic=%2Fcom.vmware.vcloud.install.doc_51%2FGUID-C258BED7-9664-4DFEB812-100281D4D460.html