A) Ultimately, he commits cold-blooded murder.
Explanation: foreshadowing is a giving a warning, an indication, or a hint of something that will happen in the future in a story. In the given passage from "The Most Dangerous Game" the phrase “Did not make me condone cold-blooded murder,” finished Rainsford stiffly, foreshadows that Rainsford will commit cold-blooded murder, in fact at the end of the story, he kills Zaroff and sleeps in his bed.