Why Would You Expect to See No Craters, Such as Those

Why would you expect to see no craters, such as those on the Moon or Mars, on Io, the innermost Galilean satellite of Jupiter?

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