Does a more sterically hindered alkyl halide correspond to a slower or faster S_N2 reaction rate?

• A. A sterically hindered alkyl halide slows down an S_N2 reaction.
• B. A sterically hindered alkyl halide speeds up an S_N2 reaction.
• C. The rate of S_N2 reactions has nothing to do with the steric effect of alkyl halides.
• D. A sterically hindered alkyl halide cannot undergo an S_N2 reaction.

Answer: (A)