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: Gynaecology & Obstetrics
[{'content': 'Protective bacterium in normal vagina is: September 2012 \nSelect and explain. \nA. Peptostreptococcus, B. Lactobacillus, C. Gardenella vaginalis, D. E. coli', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Lactobacillus', 'role': 'assistant'}]