The Mechanism That Appears to Generate Two Extensive Regions of Radio

Multiple Choice

The mechanism that appears to generate two extensive regions of radio emission near active galaxies is

A) two very hot gas clouds, suspended by magnetic fields above the rotation axis of a galaxy, emitting 21-cm radio waves.
B) a radio source split by a dark absorbing disk across its center as seen from Earth.
C) the double image of a single source behind the galaxy produced by gravitational lensing by the galaxy.
D) two oppositely directed jets of energetic particles that collide with intergalactic gas.