the nervous system and the digestive system the digestive system and the circulatory system the respiratory system and the nervous system the muscular system and the nervous system
I gave my students this multiple choice question: Which two systems of the body are interacting when a runner sprains his ankle?

Only one answer is correct among these 4 choices:
- the nervous system and the digestive system
- the digestive system and the circulatory system
- the respiratory system and the nervous system
- the muscular system and the nervous system

Could you tell me which one is correct?

the muscular system and the nervous system