A standard SCSI-1 or SCSI-2 adapter supports 7 devices, with the adapter occupying ID 7, leaving IDs 0-6 for devices. Wide SCSI and later versions support more, but typical SCSI adapter in this context refers to classic 8-bit SCSI. Answer 2 is too low, 8 doesn't account for the controller, and 2+7 is incorrect.