Which of the following factors affects a reaction rate the most?

a) activation energy
b) whether one or two reactant molecules are required
c) relative energy in reactant and product molecules
d) relative masses of reactant and product molecules

I think the correct answer is option A. Among the factors given, the factor that affects the reaction rate the most is the activation energy. Activation energy is the energy required to allow the reaction to occur. It is an important parameter in determining reaction rates.

It was ernest rutherford