Scenario: A Citrix Administrator discovers that NO Desktop OS machines can register against a specific Delivery Controller, Controller4, after maintenance over the
weekend. The administrator logs into Controller4 and finds all services are running. Pooled Desktop OS machines are registering with other Delivery Controllers in
the environment and users are able to connect successfully.
What is preventing the Desktop OS machines from registering with Controller4?

A.
SQL Server is offline.

B.
Windows Firewall is improperly configured.

C.
Controller4 was removed from NetScaler load balancing configuration.

D.
The Active Directory machine account for Controller4 was deleted from Active Directory.