What is the primary function of the citric acid cycle in metabolism?

a. to break down food molecules into smaller components so they can be absorbed by the blood

b. to synthesize atp from the energy produced in the hydrolysis of citric acid

c. to provide the enzymes necessary for the hydrolysis of carbohydrates, fats, and proteins

d. to convert acetyl groups to co2 molecules, and provide reduced coenzymes for electron transport and synthesis of atp

e. to join two-carbon acetyl groups in a cyclic series of reactions to form glucose, which can then be used for energy