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