C. "Marjorie," Russ said. "Listen carefully. There's something you need
to know."
Explanation:
Option C would be the best ending to the scene that would create the most suspense because it began with Russ telling Marjorie to listen carefully which first gets Marjorie's attention and she is eager to hear what he wants to say.
Then, he proceeds to tell her that there is something she needs to know. This is the clincher because he already has her attention by telling her to listen carefully and then ending the scene by informing her that she needs to know something brings the most suspense.
