Assertion (A) : Some organisms like Salmon are known as Euryhaline.
Reason (R) : Euryhalines can tolerate a wide range of salinities.

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 explanation of Assertion (A).
C. Assertion (A) is true but reason (R) is false.
D. Assertion (A) is false but reason (R) is true.

Explanation

To solve the assertion-reason question, we will analyze both the assertion and the reason step by step.

### Step 1: Understanding the Assertion
The assertion states that "Some organisms like Salmon are known as Euryhaline."

- **Explanation**: Euryhaline organisms are those that can tolerate a wide range of salinities in their environment. Salmon is a well-known example of such organisms as they can live in both freshwater (rivers) and saltwater (oceans).

### Step 2: Understanding the Reason
The reason states that "Euryhalines can tolerate a wide range of salinities."

- **Explanation**: This statement is true. Euryhaline organisms have physiological adaptations that allow them to survive in environments where salinity levels vary significantly.

### Step 3: Evaluating the Relationship
Now we need to determine if the reason correctly explains the assertion.

- **Analysis**: While both the assertion and the reason are true, the reason does not specifically explain why Salmon is classified as euryhaline. The assertion points out that Salmon is an example of a euryhaline organism, but it does not provide the specific context of where Salmon lives (where freshwater and saltwater mix) that leads to its euryhaline nature.

### Conclusion
Based on the analysis:
- Both the assertion and the reason are true.
- However, the reason does not correctly explain the assertion.

Thus, the correct answer is **Option 2**: Both assertion and reason are true, but the reason is not able to explain the assertion.

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