Task: Question Answering
Input (English): Question: In relation to enzymatic inhibition: 
 Options:  <1> An irreversible inhibitor causes the denaturation of the enzyme. <2> The competing inhibitors bind to the substrate of the reaction. <3> A non-competitive inhibitor does not need to bind to the enzyme to exert its activity. <4> All inhibitors modify Vmax. <5> A competitive inhibitor increases the value of Km.
Output (English): 5