This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Fetal Skull and Maternal Pelvis, Subject name: Gynaecology & Obstetrics
Smallest transverse diameter of fetal head: 
Select and explain. 
A. Biparietal, B. Bitemporal, C. Bimastoid, D. Mentovertical
C: Bimastoid
Answer: C: Bimastoid 
Explanation: Ans. (c) Bimastoid