Which of these correctly describes how organic catalysts operate in biological reactions?

Out of the following given choices;

a. they are used up in the reactions

b. they lower the overall energy of the reactions

c. they lower the activation energy of the reactions

d. they keep the temperature of the reactions constant

The answer is C. A catalyst provides an different route for a reaction, mostly bypassing some transitional states hence lowering the reaction energy. The catalyst is not consumed in the reaction.