There are three blocks, A, B and C. A medium black square is in block A. Block B is above block A. It contains one medium black square. Finally, we have block C below block A. It contains one medium black square and one medium blue square. Below a medium yellow square is the medium black square. This object is below the medium blue square. The medium black square is touching the bottom edge of this block. The medium yellow square is below the medium blue square.
What is below the yellow thing? a medium blue square or a medium black square?
medium blue square  medium black square  both of them none of them