Why Should an Observer Expect to See No Craters, Such

Multiple Choice

Why should an observer expect to see no craters, such as those on the Moon or Mars, on Io, the innermost Galilean moon of Jupiter?

A) The continuous water rainfall quickly erodes and washes away any trace of craters.
B) Volcanoes are continuously depositing new material onto the surface.
C) The liquid surface cannot maintain a crater, just as Earth's oceans cannot.
D) The surface is always reentering the planet's interior by subduction in rapid plate tectonic motion, similar to but faster than that on Earth.