(c) : Feedback inhibition or end product inhibition is the inhibition of the activity of an enzyme catalysing some early reactions of the series by the end product of the metabolic pathway. For example a substrate A is converted into a product F through B,C,D and E intermediate products. As the concentration of end product F increases, it diffuses to allosteric enzyme (E) causing a reduced synthesis of the product B which in turn lowers the rate of enzymatic reactions in rest of the pathway.