Answer: B
Reduction of CHX3CHX2CN keeps all carbons and adds one CHX2 to the chain end, giving CHX3CHX2CHX2NHX2 (propan-1-amine). Hofmann degradation of CHX3CHX2CONHX2 loses one carbon and gives CHX3CHX2NHX2 (ethanamine). Both are primary amines, and A has one more CHX2 than B.