Explanation/Reference:
UDP is a scaled-down version of TCP. It is used like TCP, but only offers a "best effort" delivery. It is connectionless, does not offer error correction, does not sequence the packet segments, and less reliable than TCP but because of its lower overhead, it provides a faster transmission than TCP.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 3: Telecommunications and Network Security (page
86).

Section: Security Operation Adimnistration
Explanation/Reference:
This is an example of Separation of Duties because operators are prevented from modifying the system time which could lead to fraud. Tasks of this nature should be performed by they system administrators.
AIO defines Separation of Duties as a security principle that splits up a critical task among two or more individuals to ensure that one person cannot complete a risky task by himself.
The following answers are incorrect:
Programmers are permitted to use the system console. Is incorrect because programmers should not be permitted to use the system console, this task should be performed by operators. Allowing programmers access to the system console could allow fraud to occur so this is not an example of Separation of Duties..
Console operators are permitted to mount tapes and disks. Is incorrect because operators should be able to mount tapes and disks so this is not an example of Separation of Duties.
Tape operators are permitted to use the system console. Is incorrect because operators should be able to use the system console so this is not an example of Separation of Duties.
References:
OIG CBK Access Control (page 98 - 101)
AIOv3 Access Control (page 182)

Section: Security Operation Adimnistration
Explanation
Explanation/Reference:
The security perimeter is the imaginary line that separates the trusted components of the kernel and the Trusted Computing Base (TCB) from those elements that are not trusted. The reference monitor is an abstract machine that mediates all accesses to objects by subjects. The security kernel can be software, firmware or hardware components in a trusted system and is the actual instantiation of the reference monitor. The reference perimeter is not defined and is a distracter.
Source: HARE, Chris, Security Architecture and Models, Area 6 CISSP Open Study Guide, January 2002.

Section: Network and Telecommunications
Explanation/Reference:
Source: TIPTON, Harold F. & KRAUSE, MICKI, Information Security Management Handbook, 4th Edition, Volume 2, 2001, CRC Press, NY, page 164.

Explanation/Reference:
The other answers are not correct because:
"Rivest, Shamir, Adleman (RSA)" is incorrect because RSA is a "traditional" asymmetric algorithm. While it is reasonably strong, it is not considered to be as strong as ECC based systems.
"El Gamal" is incorrect because it is also a "traditional" asymmetric algorithm and not considered as strong as ECC based systems.
"Advanced Encryption Standard (AES)" is incorrect because the question asks specifically about asymmetric algorithms and AES is a symmetric algorithm.
References:
Official ISC2 Guide page: 258
All in One Third Edition page: 638
The RSA Crypto FAQ: http://www.rsa.com/rsalabs/node.asp?id=2241