Answer: The correct option is (A) 90°.
Step-by-step explanation: We are given to find the number of degrees by which the triangle ABC has been rotated counterclockwise about the origin.
From the graph, we note that
the co-ordinates of the vertices of triangle ABC are A(-8, 6), B(-5, 9) and C(-2, 6).
And, the co-ordinates of the vertices of the rotated triangle A'B'C' are (-6, -8), B(-9, -5) and C(-6, -2).
That is, the transformation is as follows :
(x, y) ⇒ (-y, x).
Since this is the transformation rule for 90 degrees counterclockwise, so the required number of degrees is 90 degrees.
Option (A) is CORRECT.