C knows the answer by deducing D is not yelling out the answer. 9 Q% P# o; I; Y b8 s+ _" Z' d% \公仔箱論壇That means D is not sure the answer by seeing one white and one black.www1.tvboxnow.com8 }; E, l2 ]/ \5 k( e
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.