This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'Periconceptional use of the following agent leads to reduced incidence of neural tube defects? \nSelect and explain. \nA. Folic acid, B. Iron, C. Calcium, D. Vitamin A', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Folic acid supplementation (4mg a day) staing 4 weeks prior to conception up to 12 weeks of pregnancy is advised.This can reduce the incidence of neural tube defects.Reference: DC Dutta&;s Textbook of Obstetrics, 8th edition, page no:472', 'role': 'assistant'}]