The event in question could affect plot development in several ways, but the option that seems most impactful is:
It shows that Buck and Thornton have a true understanding of each other’s needs.
This suggests a deepening of their bond, which is significant for character development and drives the narrative forward. A strong connection between Buck and Thornton can lead to pivotal moments in the plot, influencing their choices and actions in the face of challenges. It reinforces themes of loyalty, companionship, and the transformative power of relationships, which are central to the storyline.
The other options, while they offer insights about Buck and Thornton's dynamics, do not contribute as directly to enhancing their relationship or driving the plot as a whole.