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: Pharmacology
Drug remaining in the body after 3 half lives is: 
Select and explain. 
A. 12.50%, B. 75%, C. 87.50%, D. 94%
A: 12.50%
Answer: A: 12.50% 
Explanation: None