Explanation

Explanation/Reference:
A Synchronous token generates a one-time password that is only valid for a short period of time. Once the password is used it is no longer valid, and it expires if not entered in the acceptable time frame.
Incorrect Answers:
A: Although variable callback systems are more flexible than fixed callback systems, the system assumes the identity of the individual unless two-factor authentication is also implemented.
C: Callback systems authenticate a person, but anyone can pretend to be that person. They are tied to a specific place and phone number, which can be spoofed by implementing call-forwarding.
D: The caller ID and callback functionality provides greater confidence and auditability of the caller's identity. However, unless combined with strong authentication, any individual at the location could obtain access.
References:
Harris, Shon, All In One CISSP Exam Guide, 6th Edition, McGraw-Hill, 2013, pp. 196, 696
https://technet.microsoft.com/en-us/library/cc778189(v=ws.10).aspx

Information assets are any data or information that have value for the organization, such as financial records, customer data, intellectual property, or trade secrets. Information assets are essential for the organization to achieve its objectives and to maintain its competitive advantage. Information assets should be identified, classified, and protected according to their value, sensitivity, and criticality. International Organization for Standardization (ISO) 27001 compliance does not specify which information assets must be included in asset inventory, but rather provides a framework and a set of requirements for establishing, implementing, maintaining, and improving an information security management system (ISMS). Building an information assets register is not necessarily a resource-intensive job, but rather a necessary and beneficial one, as it helps to document and manage the information assets of the organization, and to support the risk assessment and security planning processes. Information assets inventory is required for risk assessment, as it helps to determine the scope, impact, and likelihood of the risks that may affect the information assets, and to prioritize and implement the appropriate controls and measures to mitigate the risks.

Diffie and Hellman describe a means for two parties to agree upon a shared secret in such a way that the secret will be unavailable to eavesdroppers. This secret may then be converted into cryptographic keying material for other (symmetric) algorithms. A large number of minor variants of this process exist. See RFC 2631 Diffie-Hellman Key
Agreement Method for more details.
In 1976, Diffie and Hellman were the first to introduce the notion of public key cryptography, requiring a system allowing the exchange of secret keys over non-secure channels. The
Diffie-Hellman algorithm is used for key exchange between two parties communicating with each other, it cannot be used for encrypting and decrypting messages, or digital signature.
Diffie and Hellman sought to address the issue of having to exchange keys via courier and other unsecure means. Their efforts were the FIRST asymmetric key agreement algorithm.
Since the Diffie-Hellman algorithm cannot be used for encrypting and decrypting it cannot provide confidentiality nor integrity. This algorithm also does not provide for digital signature functionality and thus non-repudiation is not a choice.
NOTE: The DH algorithm is susceptible to man-in-the-middle attacks.
KEY AGREEMENT VERSUS KEY EXCHANGE
A key exchange can be done multiple way. It can be done in person, I can generate a key and then encrypt the key to get it securely to you by encrypting it with your public key. A
Key Agreement protocol is done over a public medium such as the internet using a mathematical formula to come out with a common value on both sides of the communication link, without the ennemy being able to know what the common agreement is.
The following answers were incorrect:
All of the other choices were not correct choices
Reference(s) used for this question:
Shon Harris, CISSP All In One (AIO), 6th edition . Chapter 7, Cryptography, Page 812.
http://en.wikipedia.org/wiki/Diffie%E2%80%93Hellman_key_exchange
http://www.google.com/patents?vid=4200770