This question is based on the exercise in my English textbook:
Mark the letter A, B, C, or D on your answer sheet to indicate the most suitable response to complete each of the following exchanges.
John: "Wow, I’ve never seen such a nice cell phone, Mary"
Mary: " ___ "
A. Thank you. I’m glad you like it.
B. Oh, I don’t know.
C. I agree with you.
D. You’re welcome.
The answer key is option A (Thank you. I’m glad you like it). However, I think this response is suitable only if that cell phone belongs to Mary. If that cell phone doesn't belong to Mary, is it natural for her to say "I agree with you" (option C) when she has the same opinion as John?