Hello!
The center-radius form of the circle equation is in the format: (x – h)² + (y – k)² = r², with the center being at the point (h, k) and the radius being "r".
Since the equation is x² + y² = 49, or x² + y² = 7², because 7 is a perfect square, and there are no h and k values, the center of the circle is (0, 0), which is the last choice.