This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
[{'content': 'cGMP is second messenger for which of the following harmone \nSelect and explain. \nA. Atrial  natriuretic factor, B. Nitric acid, C. Both of the above, D. None of the above', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Atrial\xa0 natriuretic factor (ANF) and Nitric acid (NO) user cGMP as second messenger.', 'role': 'assistant'}]