A: The axoneme of eukaryotic flagellum possesses a number of microtunles running parallel to the long axis.ltBRgt R: It has a pair of peripheal doublet and pair of centrally located microtubules.

Options

A. if both Assertion & Reason are true and the reason in the correct explanation of the assertion, then mark(1).
B. if both Assertion & Reason are true and the reason in the correct explanation of the assertion, then mark(2).
C. if Assertion is the ture statement but Reason is false, then mark(3)
D. if both Assertion and Reaosn are false statements, then mark(4)

Answer

### Step-by-Step Solution

1. **Understanding the Assertion**:
- The assertion states that the axoneme of the eukaryotic flagellum possesses a number of microtubules running parallel to the long axis.
- In eukaryotic flagella, the axoneme is the structural core that contains microtubules arranged in a specific pattern.

2. **Analyzing the Structure of the Axoneme**:
- The axoneme typically exhibits a "9 + 2" arrangement of microtubules. This means there are 9 pairs of peripheral microtubules arranged in a circle and 2 central microtubules.
- The peripheral microtubules are indeed running parallel to the long axis of the flagellum.

3. **Evaluating the Reason**:
- The reason provided states that the axoneme has a pair of peripheral doublets and a pair of centrally located microtubules.
- While the peripheral microtubules are correctly described as doublets, the central microtubules are not paired; they are single and unfused.

4. **Determining the Truth of the Statements**:
- Since the assertion is true (the axoneme does contain microtubules running parallel to the long axis), we confirm that the assertion is correct.
- However, the reason is false because it incorrectly describes the central microtubules as paired when they are actually unpaired.

5. **Conclusion**:
- The assertion is true, but the reason is false. Therefore, the correct answer is that the assertion is true, but the reason is false.

### Final Answer:
- The correct answer is **Option C**: Assertion is true, but reason is false.