Answer:
C. 30 degrees
Explanation:
The blue figure is the pre-image (original); and the pink is the image (after rotating).
Rotating counter-clockwise is Positive, so eliminate choices A and B.
Rotating 90° would put each vertex point in a different quadrant, with the pre-image (x,y) becoming (-y,x).
Ex: A(-3,2) ⇒ A¹(-2,-3)
Since this is not the case, 30° is the only remaining choice.