Final answer:
Henry assists with the garden to contribute to the war effort (Option B), aligning himself with the patriotic movement of Victory Gardens during wartime.
Step-by-step explanation:
In the story "In the Victory Garden," Henry agrees to help Olive and Pearl with their garden primarily to contribute to the war effort (Option B). Victory Gardens were an essential part of the home front during wartime, as they allowed more of the nation's food supply to be directed toward the troops and reduced the burden on public food sources. Being part of the Victory Garden movement was a way for citizens to feel they were making a meaningful contribution to the war effort, beyond just recycling materials or buying war bonds. Participation in Victory Gardens was seen as a patriotic act and a morally responsible way to support the armed forces fighting overseas.