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': 'Relaxation of mesangial cells of kidney is brought about by ? \nSelect and explain. \nA. cAMP, B. Endothelin, C. PGF2, D. Vasopressin', 'role': 'user'}, {'content': 'Answer: A \nExplanation: A i.e. C-Amp', 'role': 'assistant'}]