Why Are There Two Tails to Some Comets

Why are there two tails to some comets?

A) The "gas tail" is formed by solar radiation pressure. The "dust tail," is pushed out by the solar wind.
B) The "dust tail" is formed by solar radiation pressure. The "gas tail," is pushed out by the solar wind.
C) Comets contain dense material which is attracted by the Sun's gravity, forming a tail which points toward the Sun.
D) The statement is false: comets have only one tail.