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': 'Indications of medical managemnt in ectopic pregnancy: \nSelect and explain. \nA. Presence of fetal heart activity, B. Size < 4cms, C. Gestation < 6weeks, D. ahCG > 1500', 'role': 'user'}, {'content': 'Answer: B \nExplanation: None', 'role': 'assistant'}]