Section: Security Operation Adimnistration
Explanation/Reference:
Source: TIPTON, Hal, (ISC)2, Introduction to the CISSP Exam presentation.

Explanation/Reference:
Passwords are one of the multiple ways to authenticate (prove who you claim to be) an identity which allows confidentiality controls to be enforced to assure the identity can only access the information for which it is authorized. It is the authentication that assists assurance of confidentiality not the passwords.
"Network security protocols" is incorrect. Network security protocols are quite useful in assuring confidentiality in network communications.
"Network authentication services" is incorrect. Confidentiality is concerned with allowing only authorized users to access information. An important part of determining authorization is authenticating an identity and this service is supplied by network authentication services.
"Data encryption services" is incorrect. Data encryption services are quite useful in protecting the confidentiality of information.
Reference(s) used for this question:
Official ISC2 Guide to the CISSP CBK, pp. 407 - 520
AIO 3rd Edition, pp. 415 - 580

TACACS+ is a proprietary Cisco enhancement to TACACS and is more
robust than RADIUS. PAP is not a remote access authentication system but a remote node
security protocol.
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 122).

It is recommended that testing does not exceed established frequency limits. For a plan to be effective, all components of the BCP should be tested at least once a year. Also, if there is a major change in the operations of the organization, the plan should be revised and tested not more than three months after the change becomes operational.
Source: BARNES, James C. & ROTHSTEIN, Philip J., A Guide to Business Continuity Planning, John Wiley & Sons, 2001 (page 165).

Explanation/Reference:
Other elements are included in a PKI.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, John Wiley & Sons, 2001, Chapter 4: Cryptography (page 165).