Which of the following sentences signifies a flashback?

As he entered the school for the first time, one thing stood out: the stark difference between the "popular" kids and everyone else.
I thought about it too much, almost to the point where it consumed me: the idea was a hamster on a wheel spinning in my brain.
She was looking forward to the dance; she'd designed and sewn her own dress to wear.
The unexpected boom of thunder threw my memory into reverse, and the day I lost everything came back to me in full focus.

1 answer

The sentence that signifies a flashback is:

"The unexpected boom of thunder threw my memory into reverse, and the day I lost everything came back to me in full focus."

This sentence indicates a shift in time to a past event, which is characteristic of a flashback.