Consider the S_N2 Reaction of 2-Iodopentane with CH₃CO₂- Ion

Consider the S_N2 reaction of 2-iodopentane with CH₃CO₂- ion. Assuming no other changes,what effect on the rate would result from simultaneously doubling the concentrations of both 2-iodopentane and CH₃CO₂- ion?

A) No effect.
B) It would double the rate.
C) It would triple the rate.
D) It would increase the rate four times.
E) It would increase the rate six times.