This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pediatrics
[{'content': 'When does switchover from fetal to adult hemoglobin synthesis begin – \nSelect and explain. \nA. 14 weeks gestation, B. 30 weeks gestation, C. 36 weeks gestation, D. 7–10 days postnatal', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Fetal Hb → (α2 γ2)\nAdults Hb\xa0→ (α2\xa0β2)\n\nDuring the initial fetal life, the major haemoglobin synthesized in the body is fetal haemoglobin, because, in the fetus, the chain synthesized predominantly is the γ chain.\nthe β chain is present in only trace amount in early embryos\nThe rate of synthesis of y and β chains and the amount of HbA and HbF are inversely related during the intrauterine stage.\nAs the age of the fetus increases, the synthesis of β chains and the amount of adult haemoglobin in the blood increases\nAt 36 weeks of gestational age the rate of synthesis of (β chain exceeds that of γ chain. This is called switch over.', 'role': 'assistant'}]