Assertion. Hubs and switches can be replaced.

Reason. While a hub is a broadcast device, a switch is a unicast device.

(b)

Both Assertion and Reason are true but Reason is not the correct explanation of Assertion.

Explanation
Both hubs and switches are used to connect multiple devices in a network. Hence they are replaceable with each other. Switches offer more efficient data transmission compared to hubs because they can direct data specifically to the intended device connected to it, unlike a hub that just sends data to all connected devices. This makes a switch more efficient for managing network traffic. Therefore, a hub is a broadcast device, a switch is a unicast device.