Concept:The solar system is the Sun and all the celestial bodies that travel around it due to gravity.
Explanation:The Sun is at the centre of the solar system.
Different planets, including Earth, move in fixed paths around the Sun.
The Moon revolves around the Earth, not around the Sun directly, so it is not the main feature of the solar system.
Pluto is only one member of the system, not the whole system.
The most complete and correct description is that the solar system includes the Sun and its planets.
Therefore, among the given choices, the solar system is best defined as the Sun together with its planets.
Answer:C. the sun and its nine planets