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': 'Supine hypotension is characteristic of : \nSelect and explain. \nA. 1st trimester, B. 2nd trimester, C. 3rd trimester, D. Twin pregnancy', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 3rd trimester', 'role': 'assistant'}]