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': 'Facultative organisms constituting female vaginal flora include all except \nSelect and explain. \nA. Diphtheroids, B. Streptococci, C. Lactobacilli, D. E. coli', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Lacto bacilli is main organism in vaginal flora.\nIt is not facultative.', 'role': 'assistant'}]