This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
Drug remains in the body after three lives is 
Select and explain. 
A. 12.50%, B. 87.50%, C. 75%, D. 94%
A: 12.50%
Answer: A: 12.50% 
Explanation: Cp - > Cp/2 in 1 half-life i.e. 50.0 % lost 50.0 % Cp - > Cp/4 in 2 half-lives i.e. 25.0 % lost 75.0 % Cp - > Cp/8 in 3 half-lives i.e. 12.5 % in body and lost 87.5 % Cp - > Cp/16 in 4 half-lives i.e. 6.25 % lost 93.75 % Cp - > Cp/32 in 5 half-lives i.e. 3.125 % lost 96.875 % Cp - > Cp/64 in 6 half-lives i.e. 1.563 % lost 98.438 % Cp - > Cp/128 in 7 half-lives i.e. 0.781 % lost 99.219 % Ref-KDT 7/e p30