Answer: Circumcenter (choice C)
Explanation:
The circumcenter is useful to form a circle that passes through all three points of a triangle. It is the smallest circle possible that doesn't go inside the triangle.
The incenter is formed by intersecting at least two angle bisectors, which means we can rule out choice A. The centroid is the result of intersecting two or more medians, which allows us to cross off choice B. Choice D is out because the orthocenter is the intersection of the altitudes.