Virus which has more than one serotypes ?
Ans. is 'd' i.e., Influenza Influenza virus is an enveloped RNA virus containing 8 pieces (8 segments) of single stranded RNA. There are three viral subtypes : (i) Type A (causes all pandemics and most epidemics); (ii) Type B; and (iii) Type C (not circulating currently).
Measles
Mumps
Rubella
Influenza