The correct option is A Succinic dehydrogenase by malonic acid
A classic example of competitive inhibition of an enzyme is the inhibition of succinic dehydrogenase by malonic acid. Malonic acid has a structural resemblance to succinate. So, it competes with succinate for the active site on the enzyme succinate dehydrogenase. If the concentration of malonic acid is more, the rate of the enzymatic reaction will be drastically reduced.