The correct answers are:
60°, 120°, and 180°.
Explanation:
A hexagon has six angles. A full circle is 360°; since there are 6 angles in the hexagon, it will rotate onto itself every 360/6 = 60°. This means that the hexagon will rotate onto itself at angles that are multiples of 60°; this means that 120° and 180° will also do this.