The correct answer is the sentence: "So before a battle begins, the horses paw the ground; toss their heads; the light shines on their flanks; their necks curve. So Peter Walsh and Clarissa, sitting side by side on the blue sofa, challenged each other."
Explanation:
In this sentence, the author is using the metaphor of horses preparing for battle to illustrate how the characters are behaving. Just as the horses paw the ground, challenging each other in a show of strength, Clarissa and Peter also sit next to each other preparing to challenge one another.
