During the installation of vCenter Server, if you choose Join Group, which of
the following actions is taken?

A.
The vCenter Server is joined to a Linked Mode group

B.
The vCenter Server is configured for VMware Fault Tolerance

C.
The vCenter Server is clustered with an existing vCenter Server for high availability

D.
The /etc/group file on ESX Hosts managed by vCenter Server are configured for
vpxuser authentication

Explanation:
ESX and vCenter Server Installation Guide, ESX 4.0, vCenter Server 4.0, page 91.
Install vCenter Server
10. Select Create a standalone VMware vCenter Server instance or Join Group and click
Next. Join a Linked Mode group to enable the vSphere Client to view, search, and
manage data across multiple vCenter Server systems.