Assertion (A): The inactive form of toxic proteins are advantageous to the bacteria producing it.
Reason( R): Low concentration of a bacteria or virus, even at a time when the symptoms of the disease are not visible, can be detected.

Options

A. Both assertion (A) and reason (R ) are true and reason (R ) is the correct explanation of assertion (A ) .
B. Both assertion (A) and reason ( R) are true but reason (R ) is not the correct explaination of assertion (A ) .
C. Assertion (A) is true but reason (R ) is false .
D. Assertion (A ) is false but reason (R ) is true.

Explanation

**Step-by-Step Solution:**

1. **Understanding the Assertion (A)**: The assertion states that the inactive form of toxic proteins is advantageous to the bacteria producing them. This means that bacteria can produce toxins in a form that does not harm them but can be activated later to affect their target organisms.

2. **Explaining the Inactive Toxins**: Many bacteria, such as Bacillus thuringiensis, produce inactive toxins known as protoxins. These protoxins remain inactive within the bacteria until they encounter specific conditions (like changes in pH or temperature) in the target organism, which activate the toxins.

3. **Evaluating the Reason (R)**: The reason provided states that low concentrations of bacteria or viruses can be detected even when symptoms of the disease are not visible. This is true, as modern diagnostic techniques like Polymerase Chain Reaction (PCR) allow for the detection of low levels of pathogens by amplifying their genetic material.

4. **Determining the Truth of Each Statement**:
- The assertion (A) is true because inactive toxins do provide a survival advantage to bacteria.
- The reason (R) is also true as it describes a method for detecting pathogens.

5. **Analyzing the Relationship**: While both statements are true, the reason (R) does not directly explain the assertion (A). The advantage of producing inactive toxins is not related to the detection of low concentrations of pathogens; rather, it pertains to the survival strategy of bacteria.

6. **Conclusion**: Therefore, both the assertion and reason are true, but the reason is not the correct explanation for the assertion. The correct answer is that both A and R are true, but R is not the correct explanation of A.