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: Unknown
Presentation, when the engaging diameter is Mentovertical, is? 
Select and explain. 
A. Brow, B. Face, C. Vertex, D. Breech
A: Brow
Answer: A: Brow 
Explanation: Ans-ARef.: Dutta 6th edp-393