Assertion : Virus is an obligate parasite.
Reason : Virus is host specific.

Options

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

Explanation

### Step-by-Step Solution:

1. **Understanding the Assertion**: The assertion states that "Virus is an obligate parasite." This means that viruses cannot live or reproduce independently; they must invade a host cell to replicate and carry out their life processes. This is true because viruses lack the necessary cellular machinery for metabolism and energy production.

2. **Understanding the Reason**: The reason provided is that "Virus is host specific." This means that viruses typically infect specific types of host cells. For example, some viruses infect only plant cells, while others infect only animal cells. This statement is also true.

3. **Evaluating the Relationship**: Now we need to evaluate whether the reason given is a correct explanation for the assertion. While both statements are true, the fact that viruses are host specific does not explain why they are considered obligate parasites. The obligate parasitism is primarily due to their lack of metabolic machinery, not their host specificity.

4. **Choosing the Correct Option**: Based on the analysis:
- Both the assertion and the reason are true.
- However, the reason does not correctly explain the assertion.
Therefore, the correct option is: **Option 2** - "If both assertion and reason are true and reason is not the correct explanation of assertion."