Correct figure in the following :

Explanation

In the subsequent figure one new design appears at the upper left corner and the pre-existing design moves from left to right stepwise and from right to left in one step after being rotated the through `90^(@)` clockwise. In the lower row the first and the last triangles are inverted in the first step and the other three triangles are inverted in the second step. The one triangle from the left becomes shaded and in the next step it becomes white.