Which of these is the best description of a plume? A) A channel of magma coming from the mantle to the earth's surface. B) A tubular roughly vertical body that may have been a feeder vent for a volcano. C) Large bodies of magma that solidify underground before they reach the surface of the crust. D) A tabular sheet intrusion that has intruded between older layers of sedimentary rock, beds of volcanic lava or tuff, or along the direction of foliation in metamorphic rock.