This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General obstetrics, Subject name: Gynaecology & Obstetrics
[{'content': 'During the active phase of labour, the minimum effective dilatation of the cervix in primigravida should be at the rate of \nSelect and explain. \nA. 0.5 cm/hour, B. 1 cm/hour, C. 1.5 cm/hour, D. 2.5 cm/hour', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Dilatation of cervix1cm/hr in primigravidae1.5cm/hr in multigravidaeD.C.DUTTA&;S TEXTBOOK OF GYNECOLOGY, Pg no;130,7th edition', 'role': 'assistant'}]