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 of choice for syphilis during pregnancy is : 
Select and explain. 
A. Ampicillin, B. Erythromycin, C. Benzathine penicillin, D. Tetracyclines
C: Benzathine penicillin
Answer: C: Benzathine penicillin 
Explanation: None