Choose the letter A, B, C or D to indicate the most suitable response to complete each of the following exchanges.

19. Mary: “Let’s collect all the garbage in this area.” - Nam: “__________________”

       A. Not at all.         B. Thank you for that.  C. Congratulations!     D. That’s a good idea.

20. Nam: - “That's an excellent story, Lan”      - Lan: - “__________”

A. Never mind                                                     B. No, thanks

C. It's kind of you to say so                         D. Don't say so