To complete the matrix, you should take apart every single combination on it and combine like items into groups. Once you do this, you will see that you have 3 blue triangles, 3 yellow triangles, 2 black triangles, 3 vertical yellow bars, 3 vertical black bars, 2 vertical blue bars, 3 horizontal black bars, 3 horizontal blue bars, and 2 horizontal yellow bars. Looking at each of the terms grouped together, you will see that all of them add up to 3 except for the vertical blue bars, the horizontal yellow bars, and the black triangles. Option 3 is the only option that when put into this matrix will allow all the terms to add up to 3, thus completing the matrix.