M: I'm not quite sure how to put this. But about that calculator you let me use, I dropped it. And now the "ON" button doesn't light up. ,F: Oh, that's OK. It hasn't been working right for some time.
(A) M: I fogot where I put the calculator of which the "OFF" button doesn't light up. (B) M: I’m sorry, I didn’t catch that. Would you mind speaking more slowly? (C) M: I think I damaged your calculator. (D) M: I am not sure how to solve the math problem with the calculator of which the "OFF" button doesn't light up.
C