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': 'Which of the following strains of wild poliovirus forms the salk type 1 component of inactivated polio vaccine? \nSelect and explain. \nA. MEF - 1, B. Mahoney, C. Saukett, D. Leningrad - 3', 'role': 'user'}, {'content': 'Answer: B \nExplanation: IPV is usually made from Mahoney (salk type I), MEF - 1 (salk type II) and saukett (salk type III) that are grown in cell culture. The harvested viral components are inactivated with formaldehyde. Leningrad - 3 is a strain of mumps virus used for making mumps vaccine. Ref: Park, Edition 21, Page - 185', 'role': 'assistant'}]