Which of the following is the rate law for an SN1 reaction?
a. rate = k1[alkyl halide] [nucleophile] + k2[alkyl halide]
b. rate = k1[alkyl halide] + k2[nucleophile]
c. rate = k[nucleophile]
d. rate = k[alkyl halide] [nucleophile]
e. rate = k[alkyl halide]