The correct option that shows a circle circumscribed about a triangle is the one where the triangle \( \triangle ABC \) is plotted within a circle, with a point labeled as the circumcenter. In a diagram showing a circumscribed circle, the triangle's vertices should touch the circle, and the circumcenter should be the point at which the perpendicular bisectors of the triangle's sides intersect.
Based on your descriptions, the fourth option (the one that mentions "Triangle upper A upper C upper B is plotted within a circle on a 12 by 9 unit grid. A point inside the triangle is labeled circumcenter.") seems to correctly depict a circle circumscribed about a triangle.