Which protocol is listed under the Physical Layer?

Which protocol is listed under the Physical Layer?

• A. Ethernet
• B. Bluetooth
• C. Frame Relay
• D. PPP

Answer: (B)

The Physical Layer is all about the actual transmission of raw bits over the medium, including the hardware interface and the signaling used to move those bits. Bluetooth fits here because it defines the wireless air interface—the radio frequencies, modulation, and how devices physically access the medium. In contrast, Ethernet is typically considered to span both the Physical and Data Link layers (it involves the hardware signaling plus the MAC), while PPP and Frame Relay are primarily Data Link technologies used over various physical mediums. So Bluetooth is the best match for being listed under the Physical Layer.

The Physical Layer is all about the actual transmission of raw bits over the medium, including the hardware interface and the signaling used to move those bits. Bluetooth fits here because it defines the wireless air interface—the radio frequencies, modulation, and how devices physically access the medium. In contrast, Ethernet is typically considered to span both the Physical and Data Link layers (it involves the hardware signaling plus the MAC), while PPP and Frame Relay are primarily Data Link technologies used over various physical mediums. So Bluetooth is the best match for being listed under the Physical Layer.