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: Gynaecology & Obstetrics
[{'content': 'At what level of b-HCG is it that normal pregnancy can be earliest detected by TVS: \nSelect and explain. \nA. 500 IU/m1, B. 1000 IU/m1, C. 1500 IU/m1, D. 2000 IU/m1', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is b i.e. 1000 IU/m1 PhCG level (MiU/mi) Structure visible TVS/TAS * 1000 - 1200 Gestational sac TVS * 6000 Gestational Sac TAS * 7000 Yolk sac TAS * 11000 Embryo TAS', 'role': 'assistant'}]