A 26-year-old pregnant woman has been detected to have a diastolic murmur in mitral area. Echocardiography reveals mitral valve orifice to be 0.8 cm2. The cause of her murmur is: (A) Mild mitral stenosis, (B) Severe mitral stenosis, (C) Functional murmur, (D) Transmitted murmur from the congenital hea disease of the foetus
Answer is B. Severe mitral stenosis