An example of competitive inhibitor molecule is:

Explanation

Option B is correct.An example of a competitive inhibitor molecule is sulfonamide. Sulfonamides are a class of antibiotics that work by inhibiting the enzyme dihydropteroate synthase. Dihydropteroate synthase is an enzyme that is essential for the synthesis of folic acid, which is a vitamin that is necessary for bacterial growth. Sulfonamides are competitive inhibitors of dihydropteroate synthase because they bind to the active site of the enzyme and prevent the substrate, para-aminobenzoic acid (PABA), from binding. This prevents the synthesis of folic acid and kills the bacteria. The other options are not examples of competitive inhibitors: Insecticides are chemicals that are used to kill insects. They work by a variety of mechanisms, but they do not typically inhibit enzymes. Cyanide is a toxic gas that kills cells by inhibiting the enzyme cytochrome c oxidase. However, it is not a competitive inhibitor because it does not bind to the active site of the enzyme. Metal ions are often used as cofactors for enzymes, but they can also be inhibitors. However, they do not typically act as competitive inhibitors.