Which of the following favors SN ^1 reaction?

Step-by-step solution

The S _ N 1 reaction proceeds via the formation of a carbocation intermediate in its rate-determining step. Bulky alkyl groups on the carbon atom attached to the halogen atom (such as in tertiary alkyl halides) stabilize the resulting carbocation through the +I inductive effect and hyperconjugation. Additionally, the steric crowding in the initial tetrahedral substrate is relieved when it forms a planar carbocation, which provides a driving force for the S _ N 1 mechanism. In contrast, a strong nucleophile and smal