A) just inside the Kuiper belt
B) beyond Jupiter's orbit
C) inside Mercury's orbit
D) inside Jupiter's orbit
E) They always have a tail (until they run out of material).
The answer is D inside Jupiter's orbit. They usually form at 1.5 to 2 AU from the sun. Comets can have two tails - a dust tail that points backward along the comets trajectory and an ionized gas trail that points away from the sun.
