The correct answer to this question is B, Red giant. Many don't realize that the Sun is a star, but it is and a very important one. This is because it is at the center of our Solar System. Without the Sun, there would be no life on Earth. The Sun provides the Earth with heat.
Without the Sun, the Earth has no life on it and would be an ice-coated rock. As the name red giant would suggest, the Sun is large. It is so large that one million Earth's could fit inside of it. All of the planets revolve around the Sun, which is why here on Earth, the summertime is when we are closest to the Sun. This leads to warmer temperatures.