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
Commonest cause of non-engagement at term, in priori is : 
Select and explain. 
A. CPD, B. Hydramnios, C. Brow presentation, D. Breech
A: CPD
Answer: A: CPD 
Explanation: CPD