Your answer would be option C. x² + y² + 6x - 24y + 128 = 0.
This is because the formula for the equation of a circle is (x - [x coordinate])² + (y - [y coordinate])² = radius², so you have to substitute in the coordinates and the radius, and then expand and simplify. I have done this in paper as it is easier to write than type, but let me know if you would like me to explain any part of it.
I hope this helps!