A Citrix Administrator is upgrading NetScaler 10.1 appliances in a high availability (HA) pair to
NetScaler 10.5.
What is the first step to launch the upgrade according to Citrix best practice?

A.
Use the NetScaler Configuration Utility on the primary appliance to force HA failover.

B.
Execute the installns command on the primary appliance.

C.
Use the NetScaler Configuration Utility on the secondary appliance to force HA failover.

D.
Execute the installns command on the secondary appliance.