This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Environment and health, Subject name: Social & Preventive Medicine
[{'content': 'The vector which transmits trench fever - \nSelect and explain. \nA. Tick, B. Mite, C. Flea, D. Louse', 'role': 'user'}, {'content': "Answer: C \nExplanation: Trench fever is caused by Rickettsia quintana. The vector being lice. Other diseases transmitted by lice include epidemic typhus, dermatitis, relapsing fever. REFERENCE: PARK'S TEXTBOOK OF PREVENTIVE AND SOCIAL MEDICINE, 25TH EDITION, PG NO. 837", 'role': 'assistant'}]