M: My kid is busy at school. He is the monitor in his class. ,F: Mine too, but he is the study monitor.
(A) M: I am afraid I did not quite catch what you were saying. Please repeat it. (B) M: So, you mean your son is the doctor at school. Actually my kid is the monitor in his class but he is not busy at school. (C) M: Really?  You son is the study monitor at school? Oh, my kid is not the monitor in his class. (D) M: OK, I see. You son is the study monitor at school.
D