There are three blocks, A, B and C. Block C is to the left of blocks B and A. Block A has one medium black square and one medium blue square. Below the medium blue square is the medium black square. Block B contains a medium black square. A medium yellow square is below the medium black square. And block C contains a medium yellow square and one medium blue square. The medium yellow square is below the medium blue square.
Which object is to the left of a medium blue square? the medium black square which is in block A or the medium black square which is in block B?
the medium black square  which is in block A the medium black square  which is in block B both of them none of them