C knows the answer by deducing D is not yelling out the answer. ! f6 R h6 m. [; d3 v4 ^公仔箱論壇That means D is not sure the answer by seeing one white and one black. e6 y& G) N) Q7 U# b. C& C, y
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.