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': 'Venous drainage of upper pa of uterus and placenta is through : \nSelect and explain. \nA. Ovarian vein, B. Uterine vein, C. Internal iliac vein, D. None', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ovarian vein', 'role': 'assistant'}]