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
The penicillin G preparation with the longest duration of action is: 
Select and explain. 
A. Benzathine penicillin, B. Sodium penicillin, C. Potassium penicillin, D. Procaine penicillin
A: Benzathine penicillin
Answer: A: Benzathine penicillin 
Explanation: Benzathine penicillin has the longest duration of action.