Which figure is the logical next step in the sequence?
[Image shows a sequence of four squares.
1.
A square with a small black circle in the top-left corner.
2.
The square is rotated 90 degrees clockwise, now with black circles in the top-right and bottom-right corners.
3.
The square is rotated another 90 degrees clockwise, with black circles in the bottom-left, bottom-right, and top-right corners.
4.
The square is rotated another 90 degrees clockwise, with black circles in all four corners.]