Answer:
Option B 180° is the right answer.
Explanation:
Given is : GHIJ is a square and ABCDEF is a regular hexagon having common centre O.
We know that a square is symmetric at a rotational angle of 90°.
A regular hexagon is symmetric at a rotational angle of 60°.
We will find the LCM of 90 and 60, to know how much to rotate, to get a preimage.
Moreover, a hexagon needs to rotate 180 degrees to coincide with itself.
LCM(60°,90°)=180°.
So, the correct option is B. 180°.