Why Might Increasing the Concentration of a Set of Reactants

Multiple Choice

Why might increasing the concentration of a set of reactants increase the rate of reaction?

A) You have increased the chances that any two reactant molecules will collide and react.
B) You have increased the ratio of reactants to products.
C) The concentration of reactants is unrelated to the rate of reaction.
D) The rate of reaction depends only on the mass of the atoms and therefore increases as you increase the mass of the reactants.
E) none of the above