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: Anatomy
[{'content': 'The major contribution of amniotic fluid after 20 weeks of gestation : \nSelect and explain. \nA. Ultrafiltrate and maternal plasma, B. Fetal urine, C. Fetal lung fluid, D. Fetal skin', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Origin of amniotic fluid : Early week -Maternal plasma 2 nd trimester - Fetal skin Beyond 20 weeks -Fetal urine Ref: Datta Obs 9e pg 34.', 'role': 'assistant'}]