Part A:
Option B - Concurrency of Perpendicular Bisectors Theorem is the correct answer.
Concurrency of Perpendicular Bisectors Theorem states that the perpendicular bisectors of the sides of a triangle intersect in a point that is equidistant from the vertices.
Part B:
Option B- right triangle is correct.
A right-angled triangle is a triangle which have one right angle. A triangle is acute if the circumcenter lies inside the triangle and it is obtuse if the circumcenter lies outside the triangle and right if the circumcenter lies on the triangle.
