An upgrade of IaaS components fails for two servers running Website and Manager
services on each server. The administrator started the upgrade on both servers at the same
time. What is a likely cause of the failure?

A.
Each individual server upgrade must be allowed to complete before starting another
server upgrade.

B.
The Parallel Upgrade option in the upgrade wizard was not selected before starting the
upgrage

C.
The Upgrade Order option in the upgrade wizard was not specified before starting the
upgrade

D.
Wait for the first server upgrade to start processing before starting another server
upgrade.