This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Pharmacology
Which one of the following is the best drug of choice for treatment of bacterial vaginosis during pregnancy? 
Select and explain. 
A. Clindamycin, B. Metronidazole, C. Erythromycin, D. Rovamycine
B: Metronidazole
Answer: B: Metronidazole 
Explanation: Treatment of bacterial vaginosis: Sensitive to metronidazole/clindamycin Metronidazole use in the first trimester - no human evidence of teratogenesis Topical therapy using vaginal gel is effective but may not reduce the risk of pre-term delivery. ref Katzung 12th ed