What is the difference between influenza a, b and c?

Classification. Influenza viruses are RNA viruses that have segmented genome and have high antigenic diversity. They are classified by a protein inside the virus (a, b, and c). Influ a is responsible for frequent annual outbreak and has more propensity for antigenic change. B causes outbreaks every 2 to 4 years. Influ c is known to infect human and pigs but it is rare .
Genome. The viral composition is different among the 3 types. Every year a is the most common virus circulating followed by b and then c. They also have different sensitivities to antivirals.