The correct answer is D. Asteroids.
Asteroids are minor planets that orbit the Sun. They are smaller than planets, but larger than meteoroids. Asteroids are thought to have formed from the same cloud of gas and dust that formed the Sun and planets. They are found mostly between the orbits of Mars and Jupiter, in the Asteroid Belt.
Novas are exploding stars. They are not planets.
Comets are icy bodies that orbit the Sun. They have long, thin tails that are made of gas and dust. Comets are not planets.
Meteors are small pieces of rock or metal that enter Earth’s atmosphere. They burn up and create streaks of light called meteors. Meteors are not planets.