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': 'Placenta has : \nSelect and explain. \nA. 1 aery + 2 veins, B. 2 aeries + 1 vein, C. 2 aeries + 2 veins, D. 3 aeries + 3 veins', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 2 aeries + 1 vein', 'role': 'assistant'}]