There are three blocks, A, B and C. Block B is above block A and to the right of block C. Block A contains a big blue square. Block B contains one medium yellow square, a big black square and a big yellow square. The medium yellow square is below the big black square and the big yellow square. Below the big yellow square is a small yellow square. The big black square is to the left of the big yellow square. The big yellow square is touching the right edge of this block. Above the small yellow square there is the big black square. Block C has a big yellow triangle, one small black circle and a medium black square. To the right of the small black circle which is to the left of the medium black square is the big yellow triangle. To the left of the medium black square there is a medium yellow circle. There is also one small black triangle in this block. The big yellow triangle is to the right of and touching the medium yellow circle. The medium black square is touching the right edge of this block.
Which object is above a big square? the medium yellow square or the big black square?
the medium yellow square  the big black square  both of them none of them