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: Social & Preventive Medicine
[{'content': 'Saddleback/ biphasic fever is seen in: September 2004 \nSelect and explain. \nA. Typhoid, B. Dengue, C. Brucellosis, D. Trench fever', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. B i.e. Dengue', 'role': 'assistant'}]