This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: obstetrics,pediatrics and geriatrics, Subject name: Social & Preventive Medicine
[{'content': 'Most common cause of maternal moality \nSelect and explain. \nA. Postpaum hemorrhage, B. Aboion, C. Infection, D. Eclampsia', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ref:Park's Text book of Preventive and Social Medicine 25th ed", 'role': 'assistant'}]