The letter C stands for the Circumference of the circle
The center-radius form<span> of the </span>circle<span> equation is in the format (x – h)</span>2<span> + (y – k)</span>2<span> = r</span>2<span>, with the center being at the point (h, k) and the radius being "r". Therefore, the center is located at point (1, -3) and is located in the fourth quadrant, last option. Hope this answers the question.</span>
It cannot be simplified more than that. hope this helps!
