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': 'Female sex chromatin is : \nSelect and explain. \nA. XX, B. XO, C. XY, D. XXX', 'role': 'user'}, {'content': 'Answer: A \nExplanation: XX', 'role': 'assistant'}]