What component must be installed prior to

deploying a vCenter Server in vSphere 6.x?

A. vCenter Identity Services

B. Platform Services Controller

C. vCenter Single Sign-On

D. Client Integration Plug-In

Reference:

https://docs.vmware.com/en/VMware-vSphere/6.0/com.vmware.vsphere.upgrade.doc/GUID-ACCD2814-0F0A-4786-96C0-8C9BB57A4616.html