Select the correct answer. A circle with center O. Three points A, B, and C are on the circumference and a line each runs from O to these three points. A line runs from C through O to A and the angle at C is 50 degrees. In the diagram, is a diameter of the circle with center O. If m∠= 50°, what is m∠? A. 50° B. 40° C. 80° D. 100°