C knows the answer by deducing D is not yelling out the answer.
5 x7 N! F6 q& S/ Q3 y% e8 Ytvb now,tvbnow,bttvbThat means D is not sure the answer by seeing one white and one black.
6 w/ \' Q/ v5 D n% K7 P公仔箱論壇C saw B is wearing the white, hence he is wearing the black |