The correct option is B Viruses
Bird flu, Ranikhet disease and Marck’s disease are some of the common viral diseases that affect poultry. Bird flu is caused by the avian influenza H5N1 virus. Newcastle disease or Ranikhet disease is a respiratory disease caused in poultry by an Avian paramyxovirus type 1 (APMV-1) virus. Marck’s disease is a herpesvirus infection in fowls which leads to paralysis in young ones.