We asked you to identify which of the four buried prisoners was correctly able to identify their own hat colour, and why they could be sure of it.
The answer is: C.
Neither A nor B can see anything other than the brick wall and they therefore have no information.
D can see both B and C, but since they are wearing one hat of each colour he cannot tell what colour he is wearing himself.
C therefore realises from D’s silence that he must be wearing a hat of the opposite colour to B.
Did you get it right? Why not tell the world how clever you are?