Which of the Following Statements Describes the Surface of Callisto

Which of the following statements describes the surface of Callisto, the outer Galilean satellite of Jupiter?

A) dark, rocky surface with a thin ice frost that occasionally disappears by evaporation in sunlight
B) ammonia and methane ice surface, with methane clouds above it, making the satellite appear very bright
C) sulfur-coated surface, with molten sulfur lakes and active volcanoes
D) ice-covered surface with dark coating, maybe of meteoritic dust or hydrocarbon material, making the satellite appear dark