Final answer:
C6H5CH2Br (option C) is the best candidate for an SN1 reaction with benzylamine due to the stabilization of the resulting carbocation through resonance.
Step-by-step explanation:
The student is asked to identify the alkyl halide that would best react with benzylamine through an SN1 mechanism. An SN1 reaction involves the formation of a carbocation intermediate; hence, the best substrate would be one that can form a stable carbocation. Among the options provided, C6H5CH2Br (option C) is most suited for the SN1 reaction due to the possibility of resonance stabilization of the resulting benzyl carbocation. Meanwhile, compounds like CH3Br, C2H5Br (option A and D) typically undergo SN2 reactions due to their smaller sizes that allow for backside attack, while C6H5Br (option B) is less likely to undergo an SN1 reaction because the phenyl carbocation that would be formed is not a stable intermediate.