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': 'Average blood loss in normal menstruation: \nSelect and explain. \nA. 50 ml, B. 80 ml, C. 100 ml, D. 120 ml', 'role': 'user'}, {'content': 'Answer: A \nExplanation: None', 'role': 'assistant'}]