What are asteroids primarily made of?

Asteroids are primarily made of rock and metal, which is reflected in the correct answer. Most asteroids are remnants from the early solar system that never coalesced into planets, and they typically consist of a mixture of various minerals and metallic elements. The metallic components often include iron and nickel, while the rocky components can consist of silicate materials.

This composition contrasts significantly with other celestial bodies; for example, gas giants are largely composed of gases and ices, while comets primarily consist of water ice and dust. Hence, the focus on rock and metal distinctly aligns with the known traits of asteroids, making this answer the most accurate representation of their composition.