You are working as a technician at Domain.com. You have been asked to troubleshoot a problem where none of 3 SCSI drives in a chain are seen. To troubleshoot this problem, you should start with checking:

A.
for SCSI-2 host adapter ID 7 or 15 and whether all the hard drives are terminated and have a consecutive ID of 0, 1 and 2.

B.
for SCSI host adapter ID 0; whether the chain is terminated and that all hard disks share the same ID.

C.
for the SCSI-2 host adapter ID 7 or 15 and whether both ends of the chain are terminated and that every hard drives has a unique ID.

D.
whether the host adapter is terminated and has a unique ID and that the 3 hard drives have a consecutive ID of 1, 2 and 3.

Explanation:
All devices on a parallel SCSI bus must have a SCSI ID. The initiator (adapter or controller) SCSI ID is usually set by a physical jumper or switch. The target (disk-drive) SCSI IDs are either set by physical jumpers or by control signals which vary for each connector on an enclosure backplane.