Why are coaxial cables called “coaxial”?

A.
it includes two physical channels that carries the signal surrounded (after a layer of insulation) by another
concentric physical channel, both running along the same axis.

B.
it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another
concentric physical channel, both running along the same axis.

C.
it includes two physical channels that carries the signal surrounded (after a layer of insulation) by another
two concentric physical channels, both running along the same axis.

D.
it includes one physical channel that carries the signal surrounded (after a layer of insulation) by another
concentric physical channel, both running perpendicular and along the different axis

Explanation:
Coaxial cable is called “coaxial” because it includes one physical channel that carries the signal surrounded
(after a layer of insulation) by another concentric physical channel, both running along the same axis. The outer
channel serves as a ground. Many of these cables or pairs of coaxial tubes can be placed in a single outer
sheathing and, with repeaters, can carry information for a great distance.
STEINER, Kurt, Telecommunications and Network Security, Version 1, May 2002, CISSP Open
Study Group (Domain Leader: skottikus), Page 14.