Explanation/Reference:
Digital Audio Tape (DAT) can be used to backup data systems in addition to its original intended audio uses.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 70.

Section: Access Control
Explanation/Reference:
Synchronous dynamic password tokens generate a new unique password value at fixed time intervals, so the server and token need to be synchronized for the password to be accepted.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 2: Access control systems (page 37).
Also check out: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, chapter 4: Access Control (page 136).

A covert channel is an unintended communication path within a system,
therefore it is not protected by the system's normal security mechanisms. Covert channels
are a secret way to convey information.
Covert channels are addressed from TCSEC level B2.
The following are incorrect answers:
A trusted path is the protected channel that allows a user to access the Trusted Computing
Base (TCB) without being compromised by other processes or users.
A protection domain consists of the execution and memory space assigned to each
process.
A maintenance hook is a hardware or software mechanism that was installed to permit
system maintenance and to bypass the system's security protections.
Reference used for this question:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten
Domains of Computer Security, John Wiley & Sons, 2001, Chapter 6: Operations Security
(page 219).

Means, motive, and opportunity are the three items needed to commit a crime.