Final answer:
The best active listening response to concern about Sophie's behavior changes is, "It seems like you have noticed some changes in Sophie's behavior. I can see why you are worried."
Step-by-step explanation:
Using the technique of active listening, the response that best reflects this approach to the statement "I am really worried about Sophie. She has missed a lot of class lately, and she never wants to hang out anymore" would be option 3: "It seems like you have noticed some changes in Sophie's behavior. I can see why you are worried." This response acknowledges the speaker's concern and reflects understanding without making assumptions or offering unsolicited advice, which is key in active listening.