a medium planet with an atmosphere. a star composed of carbon and nitrogen. a black hole that was once a star. a star composed of hydrogen and helium.
I gave my students this multiple choice question: What is at the center of our solar system?

Only one answer is correct among these 4 choices:
- a medium planet with an atmosphere.
- a star composed of carbon and nitrogen.
- a black hole that was once a star.
- a star composed of hydrogen and helium.

Could you tell me which one is correct?

a star composed of hydrogen and helium.