This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
What percent of cardiac output goes to the kidneys? 
Select and explain. 
A. 6%, B. 10%, C. 14%, D. 22%
D: 22%
Answer: D: 22% 
Explanation: Blood flow to the kidneys accounts for 22% of cardiac output. In general, the kidneys filter 160 liters of blood per day. Ref: Essentials of Pathophysiology By Carol M. Poh Page 642.