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
A patient is administered 200 mg of a drug. 75 mg of the drug is eliminated from the body in 90 minutes. If the drug follows first order kinetics, how much drug will remain after 6 hours? 
Select and explain. 
A. 12.5 mg, B. 25 mg, C. 30 mg, D. 50 mg
C: 30 mg
Answer: C: 30 mg 
Explanation: Answer- C. 30 mgDrug remains in the body at the end of 4th 90 minutes (6 hours) : 48.7 -18.3 = 30.4 (Approx. 30 mg)