Among the following compounds, which one will undergo nucleophilic aromatic substitution at the fastest rate when treated with sodium methoxide?

Step-by-step solution

Nucleophilic aromatic substitution (SNAr) proceeds via a carbanion intermediate (Meisenheimer complex). The rate of the reaction increases with the stability of this intermediate. Electron-withdrawing groups (EWGs) stabilize the carbanion, while electron-donating groups (ERGs) destabilize it. The -CN group is a strong EWG. At the para position (in 4-chlorobenzonitrile), it stabilizes the intermediate through both strong -M (resonance) and -I (inductive) effects. At the meta position (in 3-chlorobenzonitrile), the -