Which message delivery option is used when all devices need to receive the same message simultaneously?

Broadcast

Refer to curriculum topic: 3.1.1 When all devices need to receive the same message simultaneously, the message would be delivered as a broadcast. Unicast delivery occurs when one source host sends a message to one destination host.

The sending of the same message from a host to a group of destination hosts is multicast delivery. Duplex communications refers to the ability of the medium to carry messages in both directions.