This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Excretory System (Kidney, Bladder) Acid-Base Balance, Subject name: Physiology
[{'content': 'What would tend to decrease GFR by more than 10% in a normal kidney? \nSelect and explain. \nA. Decrease in renal aerial pressure from 100 to 85 mm Hg, B. 50% decrease in afferent aeriolar resistance, C. 50% decrease in efferent aeriolar resistance, D. 50% increase in the glomerular capillary filtration coefficient', 'role': 'user'}, {'content': 'Answer: C \nExplanation: 50% reduction in efferent aeriolar resistance would cause a large decrease in GFR--greater than 10%. A decrease in renal aery pressure from 100 to 85 mm Hg would cause only a slight decrease in GFR in a normal, autoregulating kidney. A decrease in afferent aeriole resistance, a decrease in plasma colloid osmotic pressure, or an increase in the glomerular capillary filtration coefficient would all tend to increase GF', 'role': 'assistant'}]