weak force strong force gravitational force electromagnetic force
I gave my students this multiple choice question: Stars generate large amounts of energy when nuclei with small mass undergo fusion to form nuclei with larger mass. Which of the four basic forces of the universe is responsible for the energy released during fusion?

Only one answer is correct among these 4 choices:
- weak force
- strong force
- gravitational force
- electromagnetic force

Could you tell me which one is correct?

strong force