Answer:
A. Segment CD is the perpendicular bisector of segment AB.
Step-by-step explanation:
Notice that the given circles intersect at two points. When that happens, it creates a symmetrcal area where the segment uniting the intersection points is perpendicular to the diameters. In this case that segment is CD.
Additionally, the resulting segment also divides equally the segment AB, because the intersection area is symmetrical.
Therefore, the right answer is A., because a perpendicular bisector intersects with a right angle and at the middle point, like CD does in this case.
(In the image attached you can observe the process)
