Identify the Center and Radius of the Circle $x ^ { 2 } - 12 x + y ^ { 2 } - 6 y - 36 = 0$

Multiple Choice

Identify the center and radius of the circle $x ^ { 2 } - 12 x + y ^ { 2 } - 6 y - 36 = 0$ .

A) center: (12,6) radius: 216
B) center: (-6,-3) radius: 9
C) center: (6,3) radius: 36
D) center: (6,3) radius: 9
E) center: (12,6) radius: 36