Who sustains an injury during the incident in the swamp?

The correct choice is Mrs. Starch, who sustains an injury during the incident in the swamp. This event is pivotal in the narrative, as it advances the plot and highlights the dangers faced by the characters. Mrs. Starch's injury serves to showcase her character's resilience and determination, exemplifying her role as a strong authority figure while also illustrating the unexpected challenges that arise in the story's setting.

In this context, the other characters do not experience injuries during the incident, which differentiates Mrs. Starch's experience and emphasizes her significance in the unfolding events. Her injury not only affects her but also impacts the dynamics among the other characters, as they respond to her situation and adapt to the circumstances that arise from it.