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: Radiology
Normal metacarpal index is: 
Select and explain. 
A. Less than 5.4, B. 5.4 to 7.9, C. 8.4 to 10.4, D. More than 10.4
B: 5.4 to 7.9
Answer: B: 5.4 to 7.9 
Explanation: Ans. 5.4 to 7.9