Final answer:
In summarizing a narrative, the most important detail to include is Monica refusing the reward, as it signifies a defining action in the story.
Step-by-step explanation:
When summarizing a passage, it is important to include details that contribute to the overall theme or main events of the story. Options 1 and 4 provide specific details that seem secondary to the broader narrative. Option 2 provides context about Monica's personal life but does not directly relate to the story's central action. Option 3, on the other hand, introduces a pivotal moment where Monica's moral choice is highlighted, as refusing a reward is an unusual and defining action that directly affects the story's outcome. Therefore, it is the detail about refusing the reward that is most relevant to the summary.