A few factors influence the rate of reaction, including :
<em>Temperature</em>. Most reactions increase in rate as temperature increases; most reactions slow down as temperature decreases.
<em>Concentrations of the reactant</em>. Raising the concentration of a substance will increase the speed of the reaction; lowering the concentration of a substance will decrease the speed of the reaction. The limiting reactant is the reactant that is completely used up in a reaction. When this is completely used up, the reaction will stop.
<em>Catalysts</em>. These are substances that speed up the rate of the reaction by lowering the activation energy. If a catalyst is added, the rate of reactions will increase. If a catalyst is removed, the rate of reactions will decrease. Enzymes are biological catalysts used in living things to speed up internal reactions.
<em>Inhibitors</em>. These are substances that slow down the rate of a reaction. If an inhibitor is added to a reaction, its rate will decrease. If an inhibitor is removed from a reaction, its rate will increase.
Thus, the right answer is B. Lowering the concentration of the reactants