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: Pharmacology
[{'content': 'Amrinone acts by- \nSelect and explain. \nA. Inhibiting phosphodiesterase, B. ATPase inhibitor, C. Calcium channel blocker, D. IC/ channel opener', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Inhibiting phosphodiesterase o Amrinone inhibits phosphodiesterase III", 'role': 'assistant'}]