Assertion: Competitive inhibitors compete with natural substrate for their attachment on the active sites of enzymes.
Reasoning: In competitive inhibition, inhibitor binds to the allosteric site of the enzyme.

Assertion (A) is true but Reasoning (R) is not correct.

The correct answer is 3. Assertion (A) is true but Reasoning (R) is not correct.

Assertion (A) is true. Competitive inhibitors compete with natural substrate for their attachment on the active sites of enzymes. This means that they have a similar structure to the natural substrate and can bind to the active site of the enzyme. When the inhibitor binds to the active site, it prevents the natural substrate from binding and being converted into a product.

Reasoning (R) is not correct. In competitive inhibition, the inhibitor binds to the active site of the enzyme, not the allosteric site. The allosteric site is a different site on the enzyme that is not involved in the catalysis of the reaction. When an inhibitor binds to the allosteric site, it can change the shape of the enzyme and make it less likely that the natural substrate will bind to the active site.