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': 'Most common form of vaginitis : \nSelect and explain. \nA. Senile vaginitis, B. Trichomonas vaginitis, C. Gonococal vaginitis, D. Monilia vaginitis', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Trichomonas vaginitis', 'role': 'assistant'}]