A planet is discovered in orbit around another star. The planet has an average density of 2 g/cc. What can you infer about the nature/interior of the planet?

A) It is mostly made of ice.
B) It is mostly made of rock.
C) It has a rocky core and an ice mantle.
D) It is an equal mixture of ice, rock, and iron.
E) It's likely to be none of the above.