Big question last question someone

which group best describes the order of events in the development of the airplane?

group a
hot-air balloon flights pioneer air travel
aviators fly gliders—heavier-than-air aircraft with no engines
development of engine-powered machines with propellers and lightweight motors
first-ever flight across the english channel
construction of the first military airplanes
world's first scheduled commercial airline

group b
development of engine-powered machines with propellers and lightweight motors
world's first scheduled commercial airline
first-ever flight across the english channel
hot-air balloon flights pioneer air travel
aviators fly gliders—heavier-than-air aircraft with no engines
construction of the first military airplanes

a.
group a

b.
group b