Which of the Following Statements Replacing the Storage Array Controller

Which of the following statements replacing the storage array controller is wrong?

A) Before plugging and unplugging the controller, make sure that the service is stopped or has switched to the peer controller
B) Before switching services to the peer controller, check that the multipathing software in the system is installed and effective on the host.
C) Confirm Cache dirty data has been saved
D) Master-slave controller must be switched to be replaced controller for backup