C knows the answer by deducing D is not yelling out the answer.公仔箱論壇6 {7 A0 _: t+ ]& ^
That means D is not sure the answer by seeing one white and one black.
" |5 |0 \; S: h8 Btvb now,tvbnow,bttvbC saw B is wearing the white, hence he is wearing the black |