Find the Center and Radius of the Circle $x ^ { 2 } + y ^ { 2 } = 9$

Multiple Choice

Find the center and radius of the circle.
- $x ^ { 2 } + y ^ { 2 } = 9$

A) $( 0,3 ) , r = 9$
B) $( 0,0 ) , \mathrm { r } = 9$
C) $( 3,3 ) , r = 9$
D) $( 0,0 ) , r = 3$