The value of equilibrium constant is not changed in the presence of a catalyst in the reaction at equilibrium. The catalyst increases the rate of forward and reverse reaction to same extent. It does not affect the value of the equilibrium constant.
Catalyst does not initiate any reaction.
Biochemical catalysis:
Numerous reactions that occur in the bodies of animals and plants to maintain the life process are catalysed by enzymes.
Coenzymes increase the catalytic activity of enzyme.
Hence, option (a) is correct answer.