Two staircases of cubes meet at the back-left corner of the floor grid. Which drawing shows the arrangement seen from directly ABOVE, with the front edge at the bottom of the drawing?

From above you see one square for every floor square that has at least one cube on it: the whole back row, the whole left column and the single cube in front of the 3-high step: drawing (c). (a) has front and back swapped, (b) is left-right reversed and (d) misses the single low cube.