What are the center coordinates and radius of the sphere described by the equation x²+6x+y²−10y+z²−10z=5?
a) Center: (-3, 5, 5) ; Radius: 3
b) Center: (-3, -5, -5) ; Radius: 3
c) Center: (-3, -5, 5) ; Radius: 3
d) Center: (3, 5, 5) ; Radius: 3