Final answer:
The literary device used in the exchange between the boy and his mother in "The Rocking-Horse Winner" is foreshadowing, which hints at future events in the story. The correct option is option D.
Step-by-step explanation:
The exchange between the boy and his mother in "The Rocking-Horse Winner" is an example of foreshadowing. Foreshadowing is a literary device where the author gives hints or clues about what is going to happen later in the story.
This portrays the underlying tension and sets the stage for the boy's later actions where he is obsessed with finding the winning horse, an event foreshadowed by his intense conversation with his mother.
The conversations in the story may carry symbolic weight or seem metaphorical, but they are not outright comparisons like metaphors, nor do they function solely as a figure of speech. Thus, we can provide the correct option in the final answer: D. Foreshadowing.