Select the correct option based on statements below:

Assertion (A): Competitive inhibitors compete with the natural substrate for their attachment to the active sites of enzymes.
Reason (R): In competitive inhibition, the inhibitor binds to the allosteric site of the enzyme.
  
1. Both (A) and (R) are true but (R) is not the correct explanation of (A).
2. Both (A) and (R) are true and (R) is the correct explanation of (A).
3. Both (A) and (R) are false.
4. (A) is true but (R) is false.

Hint: An enzyme inhibitor is a molecule that binds to an enzyme and decreases its activity

Drugs are competitive inhibitors because they compete with the natural substrate for their attachment to the active sites of enzymes. Drugs inhibit the activities of enzymes. Hence, the assertion is correct. 

Some drugs do not bind to the enzyme’s active site. These bind to a different site of enzyme which is called the allosteric site. This binding of inhibitor at the allosteric site changes the shape of the active site in such a way that the substrate cannot recognize it.

When inhibitors are attached to the allosteric site, thus this type of inhibition is called non-competitive inhibition. Hence, the reason is wrong. Therefore, option 4th is the correct answer.