The only one of those I would trust is the site ending with EDU I hope this helps you.
Answer:
Mac Address
Explanation:
The MAC address or Media Access Control is a unique identifier that each manufacturer assigns to their devices that can connect to the network. They consist of 48 bits in hexadecimal form, grouped into 12 pairs of characters and each character is formed by four binary numbers, generally separated by a colon. MAC addresses are used in the data link layer of the OSI model, specifically in the lower Medium Access Control layer. An example of a MAC address could be:
10: 68: c5: 5e: 27: 3f.
I'd question the wording, However:
Monitor, Output device.
Keyboard, Input device.
Mouse, Input device.
Speakers Output Device.
Microphone, Input device.
Printer, Output device.
Scanner, input device.
Devices do not have to explicitly be one or the other e.g. a printer with a scanner, or headphones with a microphone.
