Which among the following is a double ring containing nitrogen base present in nucleic acids?

Identify the product '$$\mathrm{B}$$' in the following series of reactions.

$$\text { Propan - 1-ol } \xrightarrow[623 \mathrm{~K}]{\mathrm{Al}_2 \mathrm{O}_3} \mathrm{~A} \xrightarrow[\text { ii) } \mathrm{H}_2 \mathrm{O}]{\text { i) conc } \mathrm{H}_2 \mathrm{SO}_4} \mathrm{~B}$$

Conversion of benzene diazonium chloride to chlorobenzene in presence of $$\mathrm{CuCl} / \mathrm{HCl}$$ is known as

Which among the following compounds in NOT a colourless gas?