The Inner Planets Are Made Mostly of Rock and Metal

Multiple Choice

The inner planets are made mostly of rock and metal because:

A) lighter materials cannot orbit the Sun; they would fall in immediately
B) the Sun is made mostly of rock and metal and the inner planets are closest to the Sun
C) it was so hot where the inner planets formed that the lighter materials evaporated
D) Jupiter's large gravity immediately attracted all the lighter materials, and so there were few light atoms left by the time the inner planets were ready to form
E) this is an unsolved problem in astronomy