<prompt> Which of the following is an important etiological factor for nasopharyngeal carcinoma?CytomegalovirusEpstein Barr virusHuman Herpes VirusVaricella  <response>: 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. 