which statement about Mean time to repair (MTTR) is NOT true:

A、Mean time to repair (MTTR) is the expected amount of time it will take to get a device fixed and back into production after its failure.
B、MTTR can be amount of time between the actual failure and replaced the failed drive and the redundant array has completed rewriting the information on the new drive.
C、For a nonredundant hard drive in a desktop PC, MTTR is the amount of time between calls the help desk, and the point at which the replaced hard drive has been reloaded with the operating system.
D、For an unplanned reboot, the MTTR is the amount of time between the failure of the system and the point in time before it has rebooted its operating system,