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': 'To obtain true conjugate, the following factor should be substracted from the diagonal conjugate : \nSelect and explain. \nA. 0.5 cm, B. 1.2 cm, C. 2.5 cm, D. 3.0 cm', 'role': 'user'}, {'content': 'Answer: B \nExplanation: 1.2 cm', 'role': 'assistant'}]