One Reason the Planets near the Sun Are Composed Mainly

One reason the planets near the Sun are composed mainly of rock and iron may be that

A) the Sun's magnetic field attracted all the iron into the region around the Sun.
B) the Sun's heat made it difficult for ices and gases to condense near it.
C) the Sun's gravity sucked in iron and heavy material and the lighter materials floated farther away.
D) the Sun is made mostly of iron, so the planets nearest it are formed of iron.