What literary device involves the insertion of a past event in a narrative sequence?

The correct answer is flashback, as this literary device specifically refers to the technique of introducing a past event into the narrative flow of a story. A flashback allows the writer to provide background or context to the current events of the narrative. By using this device, authors can deepen readers' understanding of characters' motivations, reveal critical details about the plot, and create emotional connections through memories.

In contrast, foreshadowing hints at events that will occur later in the narrative, thereby creating anticipation. Flashforward, on the other hand, jumps ahead in time to depict events that will happen in the future, providing a glimpse of what is to come. A chronicle refers to a factual written account of important or historical events in the order of their occurrence, but it is not a literary device specifically related to narrative structure.