Pluto and Its Large Satellite, Charon, Differ from Each Other

Pluto and its large satellite, Charon, differ from each other in that:

A) Charon always turns the same side toward Pluto, while Pluto rotates relatively quickly, a situation similar to that of Earth and its Moon.
B) Pluto contains a larger fraction of rock compared to ice than does Charon, as indicated by Pluto's higher density.
C) Pluto has a methane atmosphere, whereas Charon has a nitrogen atmosphere.
D) Pluto has a surface of methane, nitrogen, and carbon monoxide ice, whereas Charon has a surface of water ice.