Answer:
D. 90°
Explanations:
First, find the coordinates points A, B, and C in △ABC, and the coordinates of A', B', and C' in △A'B'C'
A(-5, 3), B(-4, 6), C(-2, 4)
A'(-3, -5), B'(-6, -4), C'(-4, -2)
By observation of the coordinates of the given triangles, it will be noted that each point of the △ABC changes from from coordinates (x, y) to coordinates (-y, x) in △A'B'C'. This is the 90 degrees counterclockwise rule
△ABC is rotated 90 degrees counterclockwise about the origin to produce △A'B'C'.