The correct option is (b).
Explanation
The planets of the solar system are classified into two distinct groups based on their position relative to the asteroid belt and their physical composition: Inner Planets (Terrestrial planets) and Outer Planets (Jovian planets). The asteroid belt, situated between the orbits of Mars and Jupiter, acts as the boundary between these two groups.
Analysis of the Planets:
- 1. Neptune: Incorrect. Neptune is the eighth planet from the Sun, located far beyond the asteroid belt. It is classified as an Outer Planet (specifically an Ice Giant) and is composed primarily of gases and ices.
- 2. Mars: Correct. Mars is the fourth planet from the Sun. It is located inside the asteroid belt and is a terrestrial planet with a solid, rocky surface.
- 3. Venus: Correct. Venus is the second planet from the Sun. It is an Inner Planet with a rocky composition and high density.
- 4. Earth: Correct. Earth is the third planet from the Sun. It is the largest of the Inner Planets and possesses a solid crust and mantle.
Key Takeaway:
The Inner Planets are Mercury, Venus, Earth, and Mars; they are characterized by being smaller, denser, and rocky (Terrestrial). The Outer Planets are Jupiter, Saturn, Uranus, and Neptune; they are larger, less dense, and gaseous (Jovian).