Correct Option: D

If a reversible inhibitor can bind to the enzyme active site in place of the substrate, it is described as a “competitive inhibitor.” In pure competitive inhibition, the inhibitor is assumed to bind to the free enzyme but not to the enzyme-substrate (ES) complex. At the macroscopic level, the effect of competitive inhibition is to increase the substrate concentration required to achieve a given reaction velocity; in other words, to raise the Km. Here, with increase in the concentration of the inhibitor [I], the rate of the reaction changes and so does the slope of the plot. Hence it is a competitive inhibition.