There are three blocks, A, B and C. Block C is below A. Block A is below B. Block A contains a medium black square, one medium black triangle and one big black square. Near to, above and to the left of the big black square is the medium black triangle. Block B contains one medium yellow square. Block C contains a small black triangle, one medium yellow square and one small blue square. To the left of the small blue square is the small black triangle. It is above the medium yellow square. The medium yellow square is near to the small blue square. The small blue square is touching the right edge of this block.
Which object is below a medium yellow square? the medium black triangle or the big black square?
the medium black triangle  the big black square  both of them none of them