Answer:
c). every segment has infinitely many bisectors
Explanation:
A bisector divides a line segment in two equal parts. A line can have an undefined length but any bisector passing through the segment in a plane divides the segment in to two equal parts. And it is also possible that there may be infinite bisectors that can pass through the the same bisector points at different angles to divide the line segment in a plane in equal parts of two.
Therefore, every segment in a plane has many bisectors.