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