Answer:
The answer is B.180°.
Explanation:
The figure is rotationally symmetric is after a rotation of a given angle, it still look the same.
In this case of a rectangle, the only way to rotate it so that is look the same, is by rotating it by multiple of 180°, so that the up and down sides flip over, as well as the right and left sides.
Therefore, the only option that applies is B.180°