Identifying Flashback in Literature

In literature, a flashback is a narrative technique where the author presents events that occurred before the current timeline of the story. This technique is often used to provide background or context to the characters’ current situations. Consider the following passage:

'As she gazed out at the now peaceful lake, memories flooded back to the summer of her childhood when she and her brother would spend entire afternoons skipping stones along the water's edge.'

Which of the following sentences exemplifies the use of flashback?