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
If Renal Blood flow is 1250 ml / min. Calculate renal plasma flow ________ 
Select and explain. 
A. 690  ml / min, B. 650  ml / min, C. 710  ml / min, D. 670  ml / min
A: 690  ml / min
Answer: A: 690  ml / min 
Explanation: Renal Blood flow = 1250 ml / min
(Plasma = 100 - pcv)
In blood, by hemoatocrt, pcv = 45%, plasma = 55%
Renal plasma flow
= Renal blood flow  × % of plasma
= 1250 × 55%
= 687.5 ml / min
= 690 ml / min