Stylistically, why would the author go into detail on all types of discrimination and then state simply "It all started on a bus?"

a.
The author wants to show the contrast between the numerous acts of discrimination versus a simple act of a bus boycott.

b.
The author wants to simply inform the reader.

c.
The author wants to show that the bus boycott was not a powerful enough act of defiance.

d.
The author wants to entertain the reader.​