Information classification should be based on the value of the information to the organization and its sensitivity (reflection of how much damage would accrue due to disclosure).
Age is incorrect. While age might be a consideration in some cases, the guiding principles should be value and sensitivity.
Useful life. While useful lifetime is relevant to how long data protections should be applied,
the classification is based on information value and sensitivity.
Personal association is incorrect. Information classification decisions should be based on
value of the information and its sensitiviry.
References
CBK, pp. 101 - 102.

Explanation/Reference:
An overt channel is a path within a computer system or network that is designed for the authorized transfer of data. The opposite would be a covert channel which is an unauthorized path.
A covert channel is a way for an entity to receive information in an unauthorized manner. It is an information flow that is not controlled by a security mechanism. This type of information path was not developed for communication; thus, the system does not properly protect this path, because the developers never envisioned information being passed in this way. Receiving information in this manner clearly violates the system's security policy.
All of the other choices are bogus detractors.
Reference(s) used for this question:
KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 219.
and
Shon Harris, CISSP All In One (AIO), 6th Edition , page 380
and
Harris, Shon (2012-10-25). CISSP All-in-One Exam Guide, 6th Edition (p. 378). McGraw-Hill. Kindle Edition.

Section: Access Control
Explanation/Reference:
Secure European System for Applications in a Multi-vendor Environment (SESAME) was developed to address some of the weaknesses in Kerberos and uses public key cryptography for the distribution of secret keys and provides additional access control support.
Reference:
TIPTON, Harold, Official (ISC)2 Guide to the CISSP CBK (2007), page 184.
ISC OIG Second Edition, Access Controls, Page 111

Section: Network and Telecommunications
Explanation/Reference:
An IP spoofing attack is used to convince a system that it is communication with a known entity that gives an intruder access. It involves modifying the source address of a packet for a trusted source's address. A TCP sequence number attack involves hijacking a session between a host and a target by predicting the target's choice of an initial TCP sequence number. Piggybacking refers to an attacker gaining unauthorized access to a system by using a legitimate user's connection. A teardrop attack consists of modifying the length and fragmentation offset fields in sequential IP packets so the target system becomes confused and crashes after it receives contradictory instructions on how the fragments are offset on these packets.
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
77).

Explanation/Reference:
Simple substitution and transposition ciphers are vulnerable to attacks that perform frequency analysis.
In every language, there are words and patterns that are used more than others.
Some patterns common to a language can actually help attackers figure out the transformation between plaintext and ciphertext, which enables them to figure out the key that was used to perform the transformation. Polyalphabetic ciphers use different alphabets to defeat frequency analysis.
The ceasar cipher is a very simple substitution cipher that can be easily defeated and it does show repeating letters.
Out of list presented, it is the Polyalphabetic cipher that would provide the best protection against simple frequency analysis attacks.
Source: HARRIS, Shon, All-In-One CISSP Certification Exam Guide, McGraw-Hill/Osborne, 2002, Chapter
8: Cryptography (page 507).
And : DUPUIS, Clement, CISSP Open Study Guide on domain 5, cryptography, April 1999.