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 in a normal person is 
Select and explain. 
A. 2.1, B. 3.2, C. 4.6, D. 5.9
B: 3.2
Answer: B: 3.2 
Explanation: None