Which Statement is correct about FDM$?$

Group of answer choices

A model for circuit$-$switching that allows a user to transmit at a certain frequency band allocated to them.

A model for packet$-$switching that allows a user to transmit at a certain frequency allocated to them.

A model for circuit$-$switching that allows a user to transmit at a certain timeslot allocated to them.

A model for packet$-$switching that allows a user to transmit using a certain code to determine their possession of a certain resource.