Which of the following correctly describes the types of physical medium used in networking?

Physical medium can be copper, which uses light signals. It can also be fiber, which uses electrical signals, or Wi$-$Fi$,$ which uses radio frequencies

Physical medium can be copper, which uses radio frequencies. It can also be fiber, which uses light signals, or Wi$-$Fi$,$ which uses electrical signals.

Physical medium can be copper, which uses electrical signals. It can also be fiber, which uses radio frequencies, or Wi$-$Fi$,$ which uses light signals.

Physical medium can be copper, which uses electrical signals. It can also be fiber, which uses light signals, or Wi$-$Fi$,$ which uses radio frequencies.