C knows the answer by deducing D is not yelling out the answer.
9 _( v1 A8 l+ U9 c, W+ pwww.tvboxnow.comThat means D is not sure the answer by seeing one white and one black.TVBNOW 含有熱門話題,最新最快電視,軟體,遊戲,電影,動漫及日常生活及興趣交流等資訊。9 x5 W2 p- |* E, `
C saw B is wearing the white, hence he is wearing the black |