What is jazz?

What is Jazz?
(a)The orchestration of ragtime (Early jazz bands still continued to include banjo players carrying the song on into the 1930's) causing the piano player to move his left hand up one or more octaves and other instruments to provide the bass line
(b) Stride bass piano
(c) The orchestration of Stride bass piano
What is Stride piano?
Ragtime at a slower tempo; The slowing of the tempo of ragtime