$$W$$ g of pure coal was combusted in pure dry oxygen. The carbon dioxide gas obtained was absorbed in $$0.1\ \text{M}$$ KOH solution. The complete absorption of $$CO_2$$ required $$5\ \text{cm}^3$$ of $$0.1\ \text{M}$$ KOH. The amount of coal combusted is

A

$$3\ \text{mg}$$

B

$$6\ \text{mg}$$

C

$$11\ \text{mg}$$

D

$$12\ \text{mg}$$