This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Tumors, Subject name: ENT
[{'content': 'Which of the following is an important etiological factor for nasopharyngeal carcinoma? \nSelect and explain. \nA. Cytomegalovirus, B. Epstein Barr virus, C. Human Herpes Virus, D. Varicella', 'role': 'user'}, {'content': "Answer: B \nExplanation: Ans. is 'b' i.e., Epstein Barr virusEtiology of Nasophary ngeal carcinomao Nasopharyngeal carcinoma is multifactorial in origin, the three risk factors are1) Genetic: Chinese have a higher genetic susceptibility to nasopharyngeal cancer. Even after migration to other countries2) Viral: Epstein- Bar virus is closely associated with nasopharyngeal cancer. Specific viral markers are being developed to screen people in high incidence areas.3) Environmental: Air pollution, smoking of tobacco and opium, nitrosamines from dry salted fish, smoke from burning of incense and wood have all been incriminated.", 'role': 'assistant'}]