The equation of a circle is x2 + y2 + 6y = 7. What are the coordinates of the center and the length of the radius of the circle? O A. center (0, -3) and radius 16 O B. center (0, -3) and radius 4 C. center (0, 3) and radius 4 O D. center (0, 3) and radius 16 STEM ++ 32:36