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
Pelvic outlet is said to be contracted if 
Select and explain. 
A. Interischial tuberous diameter is < 7 cm, B. Interischial tuberous diameter is < 8 cm, C. Interischial tuberous diameter is < 9 cm, D. Interischial tuberous diameter is < 10 cm
B: Interischial tuberous diameter is < 8 cm
Answer: B: Interischial tuberous diameter is < 8 cm 
Explanation: 8cm is threshold to define pelvic outlet contraction.