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: Anatomy
During the active phase of labor the minimum effective dilatation of cervix in primigravida should be at the rate of 
Select and explain. 
A. 0.5 cm/hr, B. 1cm/hr, C. 1.5 cm/hr, D. 2 cm/ hr
B: 1cm/hr
Answer: B: 1cm/hr 
Explanation: Effective dilatation of cervix in a primigravida during active phase of labor is 1cm/hr