By default, if you remove a user from an Active Directory domain who is
currently logged in to vCenter Server, which of the following actions is taken?
A.
The user can remain logged in indefinitely, but once they log out they cannot log back in
B.
The user can remain logged in for up to 24 hours
C.
The user is logged out of vCenter Server and cannot log back in
D.
The user is given a warning they are about to be logged out and given a 1 hour grace period
Answer B is Correct .
http://pubs.vmware.com/vsphere-50/index.jsp?topic=/com.vmware.vsphere.upgrade.doc_50/GUID-DD8C6FF2-1949-4C82-A4BA-578988CA7BA1.html
Removing or Modifying vCenter Server Users
When you remove users from vCenter Server, you also remove permissions granted to those users. Modifying a user or group name causes the original name to become invalid.
To remove users from vCenter Server, you must remove them from the domain or Active Directory users list.
If you remove users from the vCenter Server domain, they lose permissions to all objects in the vSphere environment and cannot log in again.
Note
Users who are logged in and are removed from the domain keep their vSphere permissions until the next validation period. The default is every 24 hours.
Removing a group does not affect the permissions granted individually to the users in that group or permissions granted as part of inclusion in another group.
If you change a user’s name in the domain, the original user name becomes invalid in the vCenter Server system. If you change the name of a group, the original group becomes invalid after you restart the vCenter Server system.