Which is an example of half-duplex communication?

The correct answer is B. Push-to-talk radio. Half-duplex communication allows transmission in both directions, but not at the same time. A push-to-talk radio is a common example because one person presses the talk button and transmits while the other side listens; then the first person stops transmitting so the other person can reply. This differs from a telephone system, which is normally full-duplex because both parties can speak and hear at the same time. FM radio broadcast is simplex, because communication normally flows in only one direction from the broadcaster to receivers. A fibre-optic pair is commonly used for full-duplex communication because separate fibers or transmit/receive paths can support simultaneous sending and receiving. In HPE Aruba Networking switch documentation, duplex is discussed as a Layer 1/Layer 2 port characteristic, with half-duplex supported for some Ethernet speeds and full-duplex used for modern switched links. Therefore, the option that best represents half-duplex behavior is push-to-talk radio.