Find the Center and Radius of the Sphere $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } - 4 x + 4 - 8 y = 0$

Multiple Choice

Find the center and radius of the sphere. $x ^ { 2 } + y ^ { 2 } + z ^ { 2 } - 4 x + 4 - 8 y = 0$

A) $C ( 2,2,4 ) ; r = \sqrt { 2 }$
B) $C ( 0,2,4 ) ; r = 4$
C) $C ( 2,4,0 ) ; r = \sqrt { 2 }$
D) $C ( 2,4,0 ) ; r= 2$
E) none of these