Statement-I: According to MOT, the process ${\mathbf{N}}_2\left(g\right)\to {\mathrm{N}}_2^{+}\left(g\right)+e^{-}$ is more endothermic than the process ${\mathrm{O}}_2\left(g\right)⟶{\mathrm{O}}_2^{+}+e^{-}$ 

Statement-2: Because electron is removed from bonding molecular orbital in ${\mathrm{N}}_2$ whereas electron is removed from antibonding molecular orbital in ${\mathrm{O}}_2$.

Statement-1 is True, Statement-2 is True; Statement-2 is a correct explanation for Statement-1 According to MOT, the process  ${\mathbf{N}}_2\left(g\right)\to {\mathrm{N}}_2^{+}\left(g\right)+e^{-}$ is more endothermic than the process  ${\mathrm{O}}_2\left(g\right)⟶{\mathrm{O}}_2^{+}+e^{-}$

Nitric oxide gas is created when ${\mathrm{N}}_2$(g) reacts with gaseous oxygen ${\mathrm{O}}_2$(g) High temperatures are used to conduct this reaction. These kinds of reactions, in which the system absorbs heat, are known as endothermic reactions.

Hence correct option is A.