Which of the following BEST explains the role of enzymes in a reaction

c. An enzyme binds to a product causing a decrease in the rate of the reaction.

a. An enzyme causes an increase in the rate of reaction by binding to a substrate.

d. An enzyme increases the temperature of a reaction so that the reaction can occur faster.

b. An enzyme increases the amount of energy needed to complete the reaction.

The Option A is correct i. e

An enzyme causes an increase in the rate of reaction by binding to a substrate.

By increasing the enzyme concentration, the maximum reaction rate greatly increases.

Conclusions:

The rate of a chemical reaction increases as the substrate concentration increases. Enzymes can greatly speed up the rate of a reaction. However, enzymes become saturated when the substrate concentration is high.