What Conclusion Can Be Drawn from the Fact That Some

What conclusion can be drawn from the fact that some planets and satellites with solid surfaces have impact craters?

A) Collisions between Solar System bodies and planetesimals were common at one time.
B) The young planets had softer surfaces.
C) Volcanoes were very active in the early stages of planet formation.
D) The Sun went through several explosions, ejecting material that scarred the planets and satellites.