We have three blocks, A, B and C. Block A contains one medium blue square. Block B is above block A. It has a medium black square. To the left of block B there is block C which has two medium blue squares. Medium blue square number one is touching the bottom edge of this block. Below a medium yellow square there is medium blue square number two. Medium blue square number one is below medium blue square number two and the medium yellow square.
What is below the yellow thing? a medium black square or a medium blue square?
medium black square  medium blue square  both of them none of them