What is the causative agent of Influenza?

The correct option is B

Myxovirus

The myxovirus group includes strains of influenza virus which infect most species of mammals and birds. Influenza is commonly known as "the flu". Flu and cold symptoms may both include a runny/blocked nose, sore throat, and cough. Flu is primarily treated with rest and fluid intake to allow the body to fight the infection on its own. An annual vaccine can help prevent the flu and limit its complications.