Assertion : Asparagus can be vegetatively propagated by the stem.
Reason : Aspargus has unbranched swollen, underground stem having circular nodes that have buds for growth of daughter plants.

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but 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 "Asparagus can be vegetatively propagated by the stem."
- To evaluate this, we need to consider the mode of reproduction in asparagus.

2. **Evaluating the Reason**:
- The reason given is "Asparagus has unbranched swollen underground stem having circular nodes that have buds for growth of daughter plants."
- We need to analyze whether this description of asparagus is accurate.

3. **Analyzing Asparagus**:
- Asparagus does have a specialized underground structure known as a rhizome, which is a type of stem.
- However, the assertion claims that it can be propagated by the stem alone, which is misleading.

4. **Correcting the Misconceptions**:
- Asparagus primarily propagates through its roots and the buds on these roots, rather than solely through the stem.
- The reason provided is also incorrect because asparagus has a branched underground stem, not an unbranched one.

5. **Conclusion**:
- Both the assertion and the reason are incorrect. Therefore, the correct answer is that both the assertion and the reason are false.

### Final Answer:
Both the assertion and the reason are false.

---