There are three blocks. We call them A, B and C. Block A is below C and block C is to the left of B. Block A contains one big blue triangle, one big black square and a medium black triangle. Near to and above a small yellow triangle which is to the left of a medium yellow circle there is the big black square. The medium black triangle is below the medium yellow circle. It is touching the right edge of this block. It is to the right of the small yellow triangle. Block B has a medium black square. And block C has one big blue circle.
What is below the big blue circle? a medium black square or a big black square?
medium black square  big black square  both of them none of them