Which of These Statements About Galactic Motions and Interactions Is

Multiple Choice

Which of these statements about galactic motions and interactions is MOST accurate?

A) Galaxies occasionally collide with one another, particularly galaxies in clusters.
B) Galaxies are so closely packed in the universe that they are always interacting with one another.
C) The universe is composed of one giant galaxy of which all observed stars are members; thus the question of interaction between galaxies is irrelevant.
D) Galaxies are so widely separated that they never interact or collide.