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
Cardiac index ratio is determined by: 
Select and explain. 
A. CO & surface area, B. SV & surface area, C. Surface area only, D. Peripheral resistance
A: CO & surface area
Answer: A: CO & surface area 
Explanation: A i.e. CO & surface area