New reassorted influenza viruses are USUALLY transmitted to human from which of the following pathways?

A) A reassortment of two avian viruses that is directly transmitted from birds to humans.
B) A reassortment of an avian virus and a human virus that is transmitted from a pig.
C) A reassortment of two pig viruses that is directly transmitted from pigs to humans.
D) A reasortment of a human virus and a pig virus that is transmitted from a bird.
E) A reassortment of two human viruses that is directly transmitted from a human.