Here's a problem to solve: Which statement describes asteroids and comets?

Among the 4 following options, which is the correct answer?

- A: Asteroids are gaseous, and comets are solid.
 
- B: Asteroids are solid, and comets are gaseous.
 
- C: Both asteroids and comets are solids.
 
- D: Both asteroids and comets are gaseous.
 