Final answer:
The solar system began as a large spinning cloud of gas and dust called the solar nebula, which collapsed to form the Sun, planets, and other celestial bodies. The correct option from the given choices is 'c. the solar nebula'.
Step-by-step explanation:
The best evidence and theoretical calculations suggest that the solar system began with a giant spinning system of gas and dust that scientists refer to as the solar nebula. This concept posits that the solar system formed 4.5 billion years ago from a rotating cloud of vapor and dust with an initial composition reflective of the Sun's current makeup. As the nebula collapsed under its own gravity, it became hotter and denser, leading to the formation of the Sun at the center, with leftover materials coalescing into planetesimals around it.
These planetesimals are the solid chunks that would eventually clump together under gravitation to form the planets and moons we see today. The rest of the debris that did not become part of the planets still exists as comets and asteroids. Through this process, delineated by the conservation of angular momentum, the solar system and all its components came into being. Therefore, the correct answer to the student's question is c. the solar nebula.