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': 'Pregnancy requirement of folic acid per day \nSelect and explain. \nA. 100 micrograms, B. 500 milligrams, C. 300 micrograms, D. 500 micrograms', 'role': 'user'}, {'content': "Answer: D \nExplanation: Ref:Park's Text book of Preventive and Social Medicine 25th ed", 'role': 'assistant'}]