There are three blocks, A, B and C. Block B is above blocks C and A. Block A contains a medium blue square. Block B contains one medium yellow square. This block also has one medium black square. Below the medium black square there is the medium yellow square. Block C contains a medium black square. Below the medium black square is a medium yellow square.
Which object is below a medium yellow square? the medium black square which is in block B or the medium black square that is in block C?
the medium black square  which is in block B the medium black square  that is in block C both of them none of them