Q 12 For nonnegative integers s and r let if r s S 3 Sol s r s r 0 if r s For positive integers m and n let m nf m n p n p g m n p 0 where for any nonnegative integer p p n f m n p m n 1 P i 0 Then which of the following statements is are TRUE A g m n g n m for all positive integers m n B g m n 1 g m 1 n for all positive integers m C g 2m 2n 2g m n for all positive integers m n D g 2m 2n g m n for all positive integers m n A B D P