The correct answer is - c. main sequence.
The Sun is the star in the Solar System. It is a star that at the present is in the faze of a main sequence star. It's light is between the yellow and white spectrum's, with the whitish being more prevalent.
It is a star that accounts for 99.86% of the total mass in the Solar System. It is by far the biggest object in it, and the only one that emits light. The Sun is also crucial for the existence of life on Earth, as it is the one that is warming up our planet.