What does it mean when computers communicate logically and physically with each other?

A.
They speak physically through headers and trailers and logically through virtual connections.

B.
They speak physically through PVCs and logically through SVCs.

C.
They speak physically when connected to a backbone network and logically when they speak to each other within the same LAN.

D.
They speak physically through electrons and network cables and logically through layers in the OSI model.

Explanation:
Systems, of course, communicate physically using network cables or
airwaves. But they also communicate logically. An FTP protocol on one system speaks
to the FTP protocol on another system and is not aware that many other protocols,
devices, and cables are involved. Protocols, services, and applications communicate
logically, and this communication is transmitted over physical means.