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