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