C knows the answer by deducing D is not yelling out the answer.os.tvboxnow.com8 ]8 G! u' |5 v5 Y
That 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。1 `5 \, r4 |# A$ ]$ r) x9 v
C saw B is wearing the white, hence he is wearing the black
C, because he saw B's hat is white and he knows D can see the color of B's and his hat. If B and his hat has the same color, D would speak out. But D kept silent, so C knows that his hat's color must be different.