Answer: A line that is a perpendicular bisector of AB
Explanation:
The given picture is of regular heptagon .
There are seven lines of symmetry for a regular heptagon.
Line of symmetry of regular heptagon are those lines which intersect each vertex and the mid point of opposite side .
Therefore, only fourth option is giving the right answer.
A line that is a perpendicular bisector of AB is the line of reflection which can regular polygon ABCDEFG reflect to map onto itself .