Since there’s no interaction with the graph, try marking the graph as readOnly and then set the correctness in the table. When I tried this, it was displaying a checkmark on the dashboard. You generally want to set the correct sink in the component that gets interacted with by the student.
Be careful when setting a graph to degrees. It will mark correct on that page, but if you refer to that graph in degrees from another screen it will revert to radians.