The Inner Two Galilean Satellites of Jupiter Differ from the Outer

Multiple Choice

The inner two Galilean satellites of Jupiter differ from the outer two by having

A) much higher average densities and almost crater-free surfaces.
B) almost the same average densities but much older, more heavily cratered surfaces.
C) much lower average densities and heavily cratered surfaces.
D) almost the same average densities but much younger, less-cratered surfaces.