Triangles DEF and D'E'F' are shown on the coordinate plane below: D
E
F
2 3 4 5 6 7 8
-8-7-6-5-4-3-2-1
F
E2
D'
What rotation was applied to triangle DEF to create triangle D'E'F'?
90° clockwise
180°
None of the above
90° counterclockwise