There are three blocks, A, B and C. Block A is above B and block B is above C. Block A contains a medium black square and a medium yellow square. Below the medium yellow square is the medium black square. Block B has one medium blue square. Block C contains three medium yellow squares. Medium yellow square number one is touching the bottom edge of this block. Medium yellow square number two is below medium yellow square number three.. Medium yellow square number one is below medium yellow square number three. It is below the medium yellow square number two.
What is below the blue object? a medium black square or a medium yellow square?
medium black square  medium yellow square  both of them none of them