A limiting reactant is the one, which:

Explanation

The limiting reactant, or limiting reagent, is the reactant that is completely consumed first in a chemical reaction. This reactant determines the maximum amount of product that can be formed because once the limiting reactant is used up, the reaction cannot proceed further. Option C is correct because it accurately describes the role of the limiting reactant in limiting product formation. Options A and B are incorrect because the limiting reactant is not necessarily determined by a smaller mass or volume, but by stoichiometric relationships. Option D is incorrect because the limiting reactant does not result in equal amounts of reactants and products; it simply limits the amount of product based on its initial amount.