Which letter labels a vertex?
A. A only
B. B
C. C
D. A and D

Answer:
C
Step-by-step explanation:
In geometry, a vertex, often denoted by letters such as P, Q, R, S, is a point where two or more curves, lines, or edges meet. As a consequence of this definition, the point where two lines meet to form an angle and the corners of polygons and polyhedra are vertices.