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': 'Size of ovary, above which considered to be malignant : \nSelect and explain. \nA. 2 cm, B. 5 cm, C. 8 cm, D. 10 cm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 5 cm', 'role': 'assistant'}]