Which of the following alkyl halides is most likely to undergo rearrangement in an S_N1 reaction?

A) 3-bromopentane
B) 2-chloro-3,3-dimethylpentane
C) 3-chloropentane
D) bromocyclohexane
E) 1-bromo-4-methylcyclohexane

Rearrangement in SN1 reactions occurs when there is a carbocation intermediate formed. In this case, the alkyl halide with the most stable carbocation intermediate will be the one most likely to undergo rearrangement. The most stable carbocation is the tertiary carbocation, followed by secondary, and then primary. Among the given options, 2-chloro-3,3-dimethylpentane has a tertiary carbon adjacent to the leaving group, making it the most likely to undergo rearrangement.