C knows the answer by deducing D is not yelling out the answer. 0 D5 \. J/ m6 z9 W公仔箱論壇That means D is not sure the answer by seeing one white and one black. 7 Z! d5 j- Z. {7 ZTVBNOW 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。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.