A daily backup is not a backup method, but defines periodicity at which backups are made.
There can be daily full, incremental or differential backups.

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

Explanation/Reference:
The following answers are incorrect because:
Accountability, confidentiality and integrity is not the correct answer as Accountability is not one of the fundamental principle of security.
Integrity, availability and accountability is not the correct answer as Accountability is not one of the fundamental principle of security.
Availability, accountability and confidentiality is not the correct answer as Accountability is not one of the fundamental objective of security.
References : Shon Harris AIO v3 , Chapter - 3: Security Management Practices , Pages : 49-52

Explanation/Reference:
Authentication is verification that the user's claimed identity is valid and is usually implemented through a user password at log-on time.
Source: KRUTZ, Ronald L. & VINES, Russel D., The CISSP Prep Guide: Mastering the Ten Domains of Computer Security, 2001, John Wiley & Sons, Page 36.