C knows the answer by deducing D is not yelling out the answer. - I2 H0 G+ ]! G( k4 @# O公仔箱論壇That means D is not sure the answer by seeing one white and one black. ) a) N& h! N) u- S3 CC 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.