The benchmark angles are angles that are used as references like- 30 degrees, 45 degrees, 60 degrees, etc.
The closest angles to given rotation angles are:
A- 40- closest to the multiple of 45 degrees.
B- 140- closest to the multiple of 45 degrees (135 degree).
C- 170- closest to the multiple of 30 degrees (closest to 180 degrees which is multiple of both 30 and 45 degrees).
D- 220 -closest to the multiple of 30 degrees (210 degree).
E- 250- closest to the multiple of 30 degrees (240 degree).
F- 310- closest to the multiple of 45 degrees (315 degree).