AIIMS 2019 Chemistry Nucleophilic Substitution Reactions MCQ Question

Option A is correct because the nucleophilic amino group (−NH₂) in NH₂−CH₂−CH₂−OH preferentially reacts at the site where a stable carbocation can form, facilitating a more favorable reaction pathway. The presence of the hydroxyl group (−OH) does not provide the same level of nucleophilicity as the amino group, which is more basic and can effectively stabilize the transition state leading to the formation of the desired product. Other options may represent pathways where the −OH group is involved, but these would not lead to the formation of a stable carbocation or are less favorable due to the weaker nucleophilicity of −OH compared to −NH₂.