Chemistry - GOC Question with Solution | TestHub

A stronger C-N bond means more double-bond character, which comes from the nitrogen lone pair being delocalised into the ring.

A -M group (CHO) at the para position pulls the lone pair in strongly, so (C) has the most double-bond character. +M groups such as OCH₃ push electrons into the ring and oppose this. At meta, neither OCH₃ nor CHO can interact by resonance with the NH₂ group, so (B) and (D) are weaker.