Find the Center (H, K) and Radius R of the Circle

Multiple Choice

Find the center (h, k) and radius r of the circle with the given equation.
- $$x ^ { 2 } + y ^ { 2 } = 9$$

A) $( h , k ) = ( 0,0 ) ; r = 3$
B) $( h , k ) = ( 3,3 ) ; r = 3$
C) $( h , k ) = ( 3,3 ) ; r = 9$
D) $( h , k ) = ( 0,0 ) ; r = 9$