Which of the following statement is correct

Options

A. The descending limb of loop of Henle is impermeable to water
B. The ascending limb of loop of Henle is permeable to water
C. The descending limb of loop of Henle is permeable to electrolytes
D. The ascending limb of loop of Henle is impermeable to water

Explanation

To determine which statement is correct regarding the structure and function of the nephron, specifically the loop of Henle, we can analyze each statement one by one.

### Step-by-Step Solution:

1. **Identify the Statements**: We have four statements to evaluate:
- A. The descending limb of the loop of Henle is impermeable to water.
- B. The ascending limb of the loop of Henle is permeable to water.
- C. The descending limb of the loop of Henle is permeable to electrolytes.
- D. The ascending limb of the loop of Henle is impermeable to water.

2. **Evaluate Statement A**:
- The descending limb of the loop of Henle is actually permeable to water. Therefore, this statement is **incorrect**.

3. **Evaluate Statement B**:
- The ascending limb of the loop of Henle is impermeable to water. It primarily allows the reabsorption of electrolytes. Therefore, this statement is **incorrect**.

4. **Evaluate Statement C**:
- The descending limb of the loop of Henle is not permeable to electrolytes; it is primarily permeable to water. Therefore, this statement is **incorrect**.

5. **Evaluate Statement D**:
- The ascending limb of the loop of Henle is indeed impermeable to water and is permeable to electrolytes. Therefore, this statement is **correct**.

6. **Conclusion**:
- The correct statement is D: "The ascending limb of the loop of Henle is impermeable to water."

### Final Answer:
The correct statement is **D: The ascending limb of the loop of Henle is impermeable to water.**