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