Which description applies to a flashback?

a a narrative skips around in time, flashing to scenes from a protagonist's earlier life
b a narrative alternates between two or more characters who are linked in some way
c a narrative begins in the present at a point when events are already in full swing, and then ends on a cliffhanger. Then, the story flashes back in time. From this point, the story unfolds chronologically until it circles back to where it began
d A narrative skips around in time, flashing to events that occur in the future

The correct description that applies to a flashback is:

a) a narrative skips around in time, flashing to scenes from a protagonist's earlier life