How does the transactional model of communication differ from the linear model?

The linear model of communication conceives of all communication of taking part in one direction, with a sender transmitting information to a receiver. In contrast, the transactional model assumes that both parties are simultaneously transmitting to and receiving from one another. In its simplest formulation the transactional model is just two simultaneous linear channels of communication, but most transactional models complicate this picture by positing that the sender and receiver interpret information received and reciprocate towards the other party.

Then what do i do after i read the excerpt? i’m not really understanding the question here.

My answer is b but i dont know if im right