This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Shock, Subject name: Surgery
In hypovolemic shock which organ should be assessed for determining under-perfusion? 
Select and explain. 
A. Kidney, B. Hea, C. Lung, D. Liver
A: Kidney
Answer: A: Kidney 
Explanation: In hypovolemic shock, kidney has to be assessed for determining under perfusion (Best clinical indicator of tissue perfusion- Urine output)