What is the best next step in the construction of the perpendicular bisector of AB?

Answer:
B
Step-by-step explanation:
Out of all the answers given as a choice B makes the most sense because the triangle AB and point of intersection of the two circles form an equilateral triangle.
In general to construct a perpendicular bisector after we drew the two circles we have to ...draw a straight line trough the points where the two circles intersect and that is our perpendicular bisector of AB.