The number of chrial centres present in 3, 4- dibromo -2 pentanol is :

The number of chiral centers present in 3, 4-dibromo-2-pentanol is

The number of chiral centres present in 3,4 -dichloropentan -2-ol is

The number of chiral centres present in [B] is .........

The number of chiral centres present in [B] is .........

Levonorgestrel is a commonly used contraceptive. The number of chiral centres present in this molecule is: