Based on the information provided, the correct answer is D. It helps create suspense by hinting that, through Russell may have had troubles as a child, there is potential for him to change as a grown up.
Foreshadowing is a literary technique in which an author hints at or suggests events that will occur later in the story. In this example, the author is using foreshadowing to hint that Russell, who was a difficult child, may have the potential to change as a grown up. This creates suspense by suggesting that there may be more to Russell's story than what is initially revealed, and that the reader should pay attention to his character development throughout the story.