gravity between the stars energy released from the stars nuclear reactions in the stars magnetic attraction between the stars
I am hesitating between 4 options to answer the following question, which option should I choose?
Question: Binary stars orbit around the center of mass of the two stars. What causes the stars to remain together?
Possibilities:
- gravity between the stars
- energy released from the stars
- nuclear reactions in the stars
- magnetic attraction between the stars

gravity between the stars