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
Area of the mitral valve in severe mitral stenosis during pregnancy 
Select and explain. 
A. 4-6 cm2, B. 1-1.5 cm2, C. 1.5-2.5 cm2, D. 0.8-1 cm2
B: 1-1.5 cm2
Answer: B: 1-1.5 cm2 
Explanation: Normal area of the mitral valve is 4-6cm2
Severe mitral stenosis is less than 1.5cm2
Critical area is less than 1cm2