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': 'A prosthetic valve patient switches to heparin at what time during pregnancy: \nSelect and explain. \nA. 28 wks, B. 32 wks, C. 36 wks, D. Post partum', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Anticoagulants in Pregnancy\n2 main anticoagulants are', 'role': 'assistant'}]