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
Pregnancy requirement of folic acid per day 
Select and explain. 
A. 100 micrograms, B. 500 milligrams, C. 300 micrograms, D. 500 micrograms
D: 500 micrograms
Answer: D: 500 micrograms 
Explanation: Ref:Park's Text book of Preventive and Social Medicine 25th ed