What is a figure bounded by two radii and the arc of a curve called?

A figure bounded by two radii and the arc of a curve is referred to as a sector. In geometry, a sector represents a portion of a circle that is enclosed by two radii emanating from the center of the circle and the connecting arc. This circular sector resembles a "slice" of pie, wherein the two radii define the angle of the sector, and the arc serves as the curved boundary. This definition aligns closely with the characteristics of a sector, making it the correct response.

In contrast, a segment typically describes a region of a circle that is bounded by a chord and the arc opposite that chord. A chord is a straight line connecting two points on the circumference of the circle, while an arc refers to a portion of the circumference of the circle itself. Thus, neither segments, chords, nor arcs fulfill the criteria set forth in the question as effectively as a sector does.