Assertion : A plant girdled upto bast will die.
Reason : Water transportation will cease.

Options

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

Explanation

To solve the question, we need to analyze both the assertion and the reason provided.

### Step-by-step Solution:

1. **Understanding the Assertion**:
- The assertion states, "A plant girdled up to bast will die."
- Girdling a plant involves removing a ring of bark (which includes the phloem) around the stem. This disrupts the transport of nutrients (food) produced in the leaves to the rest of the plant.

2. **Understanding the Reason**:
- The reason states, "Water transportation will cease."
- Water transportation in plants primarily occurs through the xylem, which transports water and minerals from the roots to the leaves.

3. **Analyzing the Impact of Girdling**:
- When a plant is girdled, the phloem is damaged, which means that the transport of food (sugars) from the leaves to the rest of the plant is interrupted. However, the xylem, which is responsible for water transport, remains intact unless the roots are also damaged.

4. **Conclusion**:
- The assertion is true because girdling will ultimately lead to the death of the plant due to the lack of nutrient transport.
- The reason is false because water transportation does not cease; it continues until the root cells die.

5. **Final Answer**:
- The correct option is: "Assertion is true, but reason is false."