This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
[{'content': 'A vaccine is available for one of the most common causes of infantile gastroenteritis. However, it has recently been recalled. The virus is \nSelect and explain. \nA. Cytomegalovirus, B. Rotavirus, C. Varicella-zoster virus, D. Adenovirus', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Rotavirus is worldwide in distribution and has been implicated as the major etiologic agent of infantile gastroenteritis. Infection with this virus varies in its clinical presentation from asymptomatic infection to a relatively mild diarrhea to a severe and sometimes fatal dehydration. The exact mode of transmission of this infectious agent is not known. Because of severe side effects, the rotavirus vaccine has been recalled and is temporarily unavailable.', 'role': 'assistant'}]