What are two valid use cases for vCenter Server ?

What are two valid use cases for vCenter Server ? (Choose two)

A.
An administrator wants to migrate virtual machines between vCenter Server instances.

B.
An administrator wants to define roles once and have them applied to all vCenter Server instances.

C.
An administrator wants to manage ESX/ESXi hosts from multiple vCenter Server instances.

D.
An administrator wants to search all inventory objects across multiple vCenter Server instances from on vSphere Client

Explanation:

Linke mode is all about searching and viewing inventory objects… not management.

The guide covers 3 things in detail
1. search objects and locate inventory objects across vcenters
2. Check multiple vcenter services
3. Propagate rules

Ref:

Page 49 from vsphere-esxi-vcenter-server-50-host-management-guide.pdf

Roles was debated so here is the excerpt THEY DO PROPAGATE!!!! pg.49 same book

The vCenter Server instance is now part of a Linked Mode group. After you form a Linked Mode group, you
can log in to any single instance of vCenter Server and view and manage the inventories of all the vCenter
Servers in the group. It might take several seconds for the global data (such as user roles) that are changed on one machine to be visible on the other machines. The delay is usually 15 seconds or less. It might take a few minutes for a new vCenter Server instance to be recognized and published by the existing instances, because group members do not read the global data very often.