A cable lock is used to attach the PC to a desk; a switch control is used to prevent powering off of a unit; and a port control (such as a diskette drive lock) is used to prevent data from being downloaded from the PC.

Explanation/Reference:
Explanation:
A prolonged power supply that is below normal voltage is a brownout.
References: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, 3rd. Edition McGrawHill/ Osborne, 2005, page 368.

A "Degausser (Otherwise known as a Bulk Eraser) has the main function of reducing to near zero the magnetic flux stored in the magnetized medium. Flux density is measured in Gauss or Tesla. The operation is speedier than overwriting and done in one short operation. This is achieved by subjecting the subject in bulk to a series of fields of alternating polarity and gradually decreasing strength.
The following answers are incorrect:Parity Bit Manipulation. Parity has to do with disk lerror detection, not data removal. A bit or series of bits appended to a character or block of characters to ensure that the information received is the same as the infromation that was sent.
Zeroization. Zeroization involves overwrting data to sanitize it. It is time-consuming and not foolproof. The potential of restoration of data does exist with this method.
Buffer overflow. This is a detractor. Although many Operating Systems use a disk buffer to temporarily hold data read from disk, its primary purpose has no connection to data removal. An overflow goes outside the constraints defined for the buffer and is a method used by an attacker to attempt access to a system.
The following reference(s) were/was used to create this question:
Shon Harris AIO v3. pg 908
Reference: What is degaussing.

Dry pipe sprinkler systems commonly are used where he ambient temperature of the space they are protecting is expected to be less than 40 F (4.4 C).
The sprinkler pipe is filled with compressed air or nitrogen that is released when a sprinkler opens and allows the dry pipe valve to open, filling the overhead pipes with water. This prevent the pipes from freezing in unattended facilities such as warehouses.
What keeps water from entering the sprinkler pipes prematurely?
The dry pipe valve is designed so that the pressure from the compressed air or nitrogen keeps the valve closed until it is needed.

Clapper Valve Interior
Look at the interior of the valve assembly in the photograph above. The waterway at the bottom is smaller than the air chamber above the clapper valve. This design enables it to enjoy the mechanical advantage of the "differential principle." The larger surface area under relatively low air pressure is able to hold back the water pressure from the smaller orifice.
In most dry pipe valves, this differential principle operates on a ratio of about 1:6; one unit of air pressure will resist six units of water pressure. If, for example, the incoming water pressure were 60 psi (4.1 bar), the differential principle created by the larger surface area would allow as little as 10 psi (0.7 bar) air pressure to keep the valve closed. Some "low- differential" dry pipe valves operate with an air to water ressure ratio of 1:1.2.
While the minimum air pressure will keep the dry pipe valve closed during normal conditions, most sprinkler fitters will put an additional 20 psi (1.4 bar) air pressure on the system to prevent inadvertent valve operation in the event of a small air leak.
The National Fire Protection Association (NFPA) 13, Standard for the installation of
Automatic Sprinkler Systems, provides guidance on minimum air pressure that must be maintained. Another important feature of this dry pipe valve is the latching device pictured in the upper left hand corner. This attachment is designed to hold the heavy dry pipe valve in the open position once it operates so that it does not interfere with water flowing to control a fire.
For additional information, refer to NFPA 13, Standard for the Installation of Automatic
Sprinkler Systems.
All of the other choices presented within the question were only detractors and not good responses for this specific question.
Reference:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten
Domains of Computer Security, 2001, John Wiley & Sons, Page 336.
And
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: GOLD EDITION, John
Wiley & Sons, 2002, page 471.
and
The United State Fire Administration at http://www.usfa.dhs.gov/downloads/pdf/coffee- break/cb_fp_2010_20.pdf

Explanation/Reference:
Explanation:
An electronic multiplexer makes it possible for several signals to share one device or resource. A multiplexer (or mux) is a device that selects one of several analog or digital input signals and forwards the selected input into a single line.
Incorrect Answers:
A: A router forwards data packets. A router does not handle signals.
C: A CSU/DSU is a digital-interface device used to connect a data terminal equipment (DTE), such as a router, to a digital circuit, such as a Digital Signal 1 (T1) line.
D: A switch forwards traffic at the data link layer of the OSI model. It does operate with multiple signals.
References:
https://en.wikipedia.org/wiki/Multiplexer