Identify compound '$$B$$' in following series of reactions?

$$\text { Acetonitrile } \xrightarrow{\mathrm{Na} / \text { alcohol }} A \xrightarrow{\mathrm{NaNO}_2 / \text { dil. } \mathrm{HCl}} B$$

Which among the following compounds is obtained when glucose react with hydrogen cyanide?

Which of the following formula represents lithium imide?

Identify the process of refining to obtain pig tin.