3) F

It is essential that you realise that the tile is in the shape of a plus. The individual squares are not the tiles.

The person only wants to use 5 tiles.

Out of the options, there are 5 tiles which will give equal number of tiles and equal area of each pattern. There is one tile which will disrupt the equilibrium

The best way to solve this is by removing one tile and seeing whether the number of tiles with a particular patter is the same or not.

If we remove A, we have 4 white tiles, 6 black tiles. Hence this is wrong.

If we remove B, we have 6 white tiles, 5 black tiles. Hence this is wrong.

If we remove C, we have 5 white tiles, 3 black tiles. Hence this is wrong.

If we remove D, we have 5 white tiles, 6 black tiles. Hence this is wrong.

If we remove E, we have 5 white tiles, 5 black tiles, 6 checked tiles. This is wrong.

If we remove F, we have 5 white tiles, 5 black tiles, 5 checked tiles and 5 spotted tiles. Hence F is correct.