Explanation/Reference:
Block ciphers do not use public cryptography (private and public keys).
Block ciphers is a type of symmetric-key encryption algorithm that transforms a fixed-size block of plaintext (unencrypted text) data into a block of ciphertext (encrypted text) data of the same length. They are appropriate for software implementations and can operate internally as a stream. See more info below about DES in Output Feedback Mode (OFB), which makes use internally of a stream cipher.
The output feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext. Just as with other stream ciphers, flipping a bit in the ciphertext produces a flipped bit in the plaintext at the same location.
This property allows many error correcting codes to function normally even when applied before encryption.
Reference(s) used for this question:
Wikipedia on Block Cipher mode at: https://en.wikipedia.org/wiki/Block_cipher_mode_of_operation and
http://www.itl.nist.gov/fipspubs/fip81.htm

The Bell-LaPadula model is a formal model dealing with confidentiality.
The Bell-LaPadula Model (abbreviated BLP) is a state machine model used for enforcing access control in government and military applications. It was developed by David Elliott Bell and Leonard J. LaPadula, subsequent to strong guidance from Roger R. Schell to formalize the U.S. Department of Defense (DoD) multilevel security (MLS) policy. The model is a formal state transition model of computer security policy that describes a set of access control rules which use security labels on objects and clearances for subjects. Security labels range from the most sensitive (e.g."Top Secret"), down to the least sensitive (e.g., "Unclassified" or "Public").
The Bell-LaPadula model focuses on data confidentiality and controlled access to classified information, in contrast to the Biba Integrity Model which describes rules for the protection of data integrity. In this formal model, the entities in an information system are divided into subjects and objects.
The notion of a "secure state" is defined, and it is proven that each state transition preserves security by moving from secure state to secure state, thereby inductively proving that the system satisfies the security objectives of the model. The Bell-LaPadula model is built on the concept of a state machine with a set of allowable states in a computer network system. The transition from one state to another state is defined by transition functions.
A system state is defined to be "secure" if the only permitted access modes of subjects to objects are in accordance with a security policy. To determine whether a specific access mode is allowed, the clearance of a subject is compared to the classification of the object (more precisely, to the combination of classification and set of compartments, making up the security level) to determine if the subject is authorized for the specific access mode.
The clearance/classification scheme is expressed in terms of a lattice. The model defines two mandatory access control (MAC) rules and one discretionary access control (DAC) rule with three security properties:
The Simple Security Property - a subject at a given security level may not read an object at a higher security level (no read-up).
The -property (read "star"-property) - a subject at a given security level must not write to any object at a lower security level (no write-down). The -property is also known as the Confinement property. The Discretionary Security Property - use of an access matrix to specify the discretionary access control.
The following are incorrect answers:
Accountability is incorrect. Accountability requires that actions be traceable to the user that
performed them and is not addressed by the Bell-LaPadula model.
Integrity is incorrect. Integrity is addressed in the Biba model rather than Bell-Lapadula.
Availability is incorrect. Availability is concerned with assuring that data/services are
available to authorized users as specified in service level objectives and is not addressed
by the Bell-Lapadula model.
References:
CBK, pp. 325-326
AIO3, pp. 279 - 284
AIOv4 Security Architecture and Design (pages 333 - 336)
AIOv5 Security Architecture and Design (pages 336 - 338)
Wikipedia at https://en.wikipedia.org/wiki/Bell-La_Padula_model

Explanation/Reference:
Ethernet uses Carrier Sense Multiple Access with Collision Detection (CSMA/CD) to minimize the effect of broadcast collisions.
The following answers are incorrect:
CSU/DSU Is incorrect because Channel Service Unit/Digital Service Unit(CSU/DSU) is a digital interface normally used to connect a router to a digital circuit.
TCP/IP Is incorrect because Transmission Control Protocol/Internet Protocol(TCP/IP) is a network protocol not an access method.
FIFO Is incorrect as it is a distractor. First In, First Out (FIFO) is typically a processing methodology in which first come, first served.
Ethernet is a frame based network technology.
References:
OIG CBK Telecommunications and Network Security (pages 437 - 438)
Wikipedia http://en.wikipedia.org/wiki/FIFO

Statistical Anomaly-Based ID - With this method, an IDS acquires data and defines a "normal" usage profile for the network or host that is being monitored. Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 49.

Section: Access Control
Explanation
Explanation/Reference:
The cost of access control must be commensurate with the value of the information that is being protected.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 49.