Which protocol will use a LUN as a way to differentiate the individual disk drives that comprise a target device?

A.
iSCSI

B.
ATA

C.
SCSI

D.
HBA

Explanation:
The question is about Using LUN Masking to Defend Against Attacks.
The answer is: A Logical Unit Number (LUN) is an address for an individual disk drive
and, by extension, the disk device itself. The SCSI protocol uses the term LUN as a way
to differentiate the individual disk drives that comprise a common SCSI target device, such
as a SCSI disk array.
Referece: CCNA: Security – Cisco Press (page 287).
Additional information:
To defend against attacks, LUN masking may be employed. In this authorization process,
a LUN is made available to some hosts and unavailable to other hosts. Generally, this
technique of LUN masking is implemented at the host bus adapter (HBA) level.
Unfortunately, when LUN masking is implemented at this level, it is vulnerable to any
attack that compromises the HBA. Benefits, with regard to security, are limited with the
implementation of LUN masking. This is because with many HBAs it is possible for an
attacker to forge source addresses.
For this reason, LUN masking is implemented mainly as a way to protect against
malfunctioning servers corrupting disks belonging to other servers. An example of where
LUN masking might be useful is in the case of Windows servers attached to a SAN. In
some instances these corrupt non-Windows volumes by attempting to write Windows
volume labels to them. In these cases, hiding the LUNs of the non- Windows volumes
from the Windows server can prevent this behavior. With the LUNs masked, the
Windows server is unaware of the non-Windows volumes and thereby makes no attempt
to write Windows volume labels to them. In today’s implementations, typically LUNs are
not individual disk drives but rather virtual partitions (or volumes) within a RAID array.