Dicoumarol (X) is an anticoagulant. The number of possible monochloro substituted isomeric derivatives and the volume of hydrogen liberated at STP by the reaction of 0.5 mol of dicoumarol with sodium are respectively

A

$$5, 22.4 \text{ dm}^3$$

B

$$5, 11.2 \text{ dm}^3$$

C

$$6, 11.2 \text{ dm}^3$$

D

$$4, 22.4 \text{ dm}^3$$