Hint: In order to determine this we refer to the definitions of a circle and a polygon and we verify if the circle holds the conditions of a polygon.
Complete step-by-step answer:
A circle is not a polygon. A circle is the set of points in a plane that are equidistant from a given point. The distance from the center is called the radius, and the point is called the center. A polygon is a closed figure on a plane formed from a finite number of lines segments connected end-to-end. As a circle is curved, it cannot be formed from line segments, as thus does not fit the conditions needed to be a polygon.
Note: In order to solve this type of question it is important to visualize the shape of the figure to understand it better. A polygon can be of any finite number of sides. The minimum number of sides to form a polygon is 3 (a triangle). A circle does not have the concept of a side.