Which of the following is correct ?

Options

A. Afferent arteriole is narrower than the efferent arteriole
B. Effect venule is narrower than vein
C. Efferent arteriole is narrow than afferent arteriole
D. Both afferent and effernet arteriole are of same diameter

Answer

To solve the question "Which of the following is correct?" regarding the relationship between the efferent and afferent arterioles, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding the Structures**:
- The afferent arteriole carries blood into the glomerulus (a network of capillaries).
- The efferent arteriole carries blood away from the glomerulus.

2. **Analyzing the Options**:
- **Option 1**: "Efferent arteriole is narrower than the afferent arteriole."
- This statement is incorrect. The efferent arteriole is actually narrower than the afferent arteriole.

- **Option 2**: "Efferent venule is narrower than the vein."
- This statement is misleading as it refers to a venule which is not relevant in this context since we are discussing arterioles.

- **Option 3**: "Efferent arteriole is narrower than the afferent arteriole."
- This statement is correct. The efferent arteriole has a smaller diameter compared to the afferent arteriole.

- **Option 4**: "Both efferent and afferent arterioles are of the same diameter."
- This statement is incorrect as they are not of the same diameter; the efferent arteriole is narrower.

3. **Conclusion**:
- The correct answer is **Option 3**: "Efferent arteriole is narrower than the afferent arteriole."