Which would increase the reaction rate?

A) decreasing the reaction temperature

B) decreasing the reactant's particle size

C) decreasing a reactant's concentration

D) increasing a reactant's particle size

B) decreasing the reactant's particle size.

If a smaller reactant size was involved the reaction would occur faster as the quantity to partake in the reaction is smaller, and it would take lesser time compared to a bigger reactant.

B) decreasing the reactants particle size