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': 'ANF is mediated by (ANF: Atrial natriuretic factor): \nSelect and explain. \nA. Inositol phosphate, B. DAG, C. CyAMP, D. CyGMP', 'role': 'user'}, {'content': 'Answer: D \nExplanation: D i.e. CyGMP', 'role': 'assistant'}]