Answer:
d. All of the above
Explanation:
Physical layer is the lowest layer of the OSI reference model that deals with the setup of physical connection to the network and with transmission and reception of signals.
Full duplex (FDx) is a bidirectional type of communication system where two end nodes send and receive data signals at the same time, and a single carrier is simultaneously used for dual communication.
To send or receive data, the participating nodes in a Full Duplex system do not have to wait for a free carrier/medium. It employs a medium that has at least two internal channels - one for sending and one for receiving.
Based on the above explanations, options A, B and C are valid and are correct ways to accomplish full-duplex (FDX) digital communications on guided medium at the physical layer (OSI Layer 1). There all of them are correct.
Just a guess, maybe you’ve been reported for having an incorrect answer two times? I’m really not sure I’m just trying to give out possibilities. Maybe if your a Brainly Helper you haven’t been active so they are giving you warnings? Does clicking on the warning tell you the reason for them? Maybe the system thinks your a robot? I’m not sure just trying to give possible reasons, but you could try contacting customer support, but they aren’t always the quickest at responding.
Have a good day!
There isn't enough info for me to answer this with complete confidence XD.
