A patient is experiencing decreased renal perfusion due to hypovolemia. Which of the following mechanisms would primarily work to restore glomerular filtration rate (GFR) towards normal?

✓ Correct Answer: Option B

In response to decreased renal perfusion, angiotensin II preferentially constricts the efferent arteriole, increasing glomerular hydrostatic pressure and thus maintaining GFR despite reduced renal blood flow. Dilation of afferent arteriole also helps, but efferent constriction is key.