Which one of the following will undergo Nucleophilic substitution, by $$\mathrm{S}_{\mathrm{N}}{ }^1$$ mechanism, fastest?

Alkyl halides undergoing S_N2 reaction do inverse

The reaction $$\mathrm{ArN_2^ + C{l^ - }\buildrel {Cu/HCl} \over \longrightarrow ArCl + {N_2} + CuCl}$$ is called as

Benzene reacts with chlorine in sunlight to give a final product