Which method sends bidirectional control commands between the controller and a device over the network?

The correct choice, which highlights the method that sends bidirectional control commands between the controller and a device over the network, is Ethernet. This is because Ethernet is designed for networking and allows the transfer of data packets between devices in a local area network (LAN). It supports full-duplex communication, which means that data can be sent and received simultaneously, making it ideal for applications that require real-time interactions, such as control commands in an AV setup.

Wi-Fi does enable wireless networking and can also support bidirectional communication, but it is generally more susceptible to interference and connection instability compared to a wired Ethernet connection. Bluetooth, while useful for short-range wireless communication, typically offers limited bandwidth and range and is not commonly used for network-based control commands in professional AV environments. Fiber optics provide high-speed data transfer over long distances but are not specifically oriented towards control command transmission in the same way that Ethernet is designed for networking applications. Therefore, Ethernet stands out as the most reliable option for sending bidirectional control commands in an AV context.