Explanation/Reference:
Explanation:
Fences come in varying heights, and each height provides a different level of security:
Fences three to four feet high only deter casual trespassers.

Fences six to seven feet high are considered too high to climb easily.

Fences eight feet high (possibly with strands of barbed or razor wire at the top) means you are serious

about protecting your property. They often deter the more determined intruder.
The barbed wire on top of fences can be tilted in or out, which also provides extra protection. If the organization is a prison, it would have the barbed wire on top of the fencing pointed in, which makes it harder for prisoners to climb and escape. If the organization is a military base, the barbed wire would be tilted out, making it harder for someone to climb over the fence and gain access to the premises.
Critical areas should have fences at least eight feet high to provide the proper level of protection. The fencing should not sag in any areas and must be taut and securely connected to the posts. The fencing should not be easily circumvented by pulling up its posts. The posts should be buried sufficiently deep in the ground and should be secured with concrete to ensure the posts cannot be dug up or tied to vehicles and extracted. If the ground is soft or uneven, this might provide ways for intruders to slip or dig under the fence. In these situations, the fencing should actually extend into the dirt to thwart these types of attacks.
Incorrect Answers:
A: Fences three to four feet high only deter casual trespassers. They are not the most effective maximum security design. Therefore, this answer is incorrect.
B: Fences six to seven feet high are considered too high to climb easily. They are not the most effective maximum security design. Therefore, this answer is incorrect.
D: Double fencing is not the most cost effective maximum security design. Two fences would cost more than one good fence. Furthermore, this answer does not state how high the two fences are. Two 3' to 4' fences would not be very secure. Therefore, this answer is incorrect.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, p. 486