[A]: Overuse improper use of antibiotics is harmful.
[R]: It may exterminate the microflora which produces antibiotics

Options

A. If both A and R are true and R is the correct explanation of A
B. If both A and R are true but R is not the correct explanation of A
C. If A is true and R is false
D. If both A and R are false

Answer

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided in the statement:

**Assertion (A):** Overuse or improper use of antibiotics is harmful.
**Reason (R):** It may exterminate the microflora which produces antibiotics.

### Step-by-Step Solution:

1. **Evaluate the Assertion (A):**
The assertion states that the overuse or improper use of antibiotics is harmful. This is true because excessive use of antibiotics can lead to various health issues, including antibiotic resistance and the destruction of beneficial bacteria in the body.

2. **Evaluate the Reason (R):**
The reason claims that overuse of antibiotics may exterminate the microflora that produces antibiotics. This statement is misleading. While it is true that antibiotics can kill beneficial bacteria, the microflora in the human body does not produce antibiotics; rather, they help in digestion and maintaining a healthy gut environment.

3. **Determine the Relationship Between A and R:**
Since the assertion is true (overuse of antibiotics is harmful), but the reason is false (microflora does not produce antibiotics), we need to categorize the relationship.

4. **Choose the Correct Option:**
Based on the evaluations:
- Both A and R are not true.
- A is true, and R is false.
Therefore, the correct answer is option three: "Assertion is true and reason is false."

### Final Answer:
The correct option is: **Third: If assertion is true and reason is false.**

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