Assertion (A): In Cuscuta, stomata remain open during night.
Reason ( R): Cuscuta is a hydrophyte.

Options

A. Both A and R are true and R is the correct explanation for A.
B. Both A and R are true but R is not the correct explanation for A.
C. A is true and R is false.
D. A is false and R is true.

Explanation

To solve the question, we need to analyze both the assertion (A) and the reason (R) provided.

### Step-by-Step Solution:

1. **Understanding the Assertion (A)**:
- The assertion states that in Cuscuta, stomata remain open during the night.
- Cuscuta, commonly known as dodder, is a parasitic plant that does not have chlorophyll and relies on other plants for nutrients.
- It is important to note that many plants, especially succulents, may keep their stomata open at night to minimize water loss due to cooler temperatures.

2. **Evaluating the Reason (R)**:
- The reason states that Cuscuta is a hydrophyte.
- A hydrophyte is a plant that grows in water or very moist environments.
- However, Cuscuta is not a hydrophyte; it is a parasitic plant that does not live in water. Therefore, this statement is incorrect.

3. **Conclusion**:
- Since the assertion (A) is true (Cuscuta does keep its stomata open at night), but the reason (R) is false (Cuscuta is not a hydrophyte), we conclude that the correct relationship is that the assertion is true and the reason is false.

### Final Answer:
- Assertion (A) is true, and Reason (R) is false.

---