Find the Center-Radius Form of the Equation of the Circle $( 0,0 )$

Multiple Choice

Find the center-radius form of the equation of the circle.
-center $( 0,0 )$ , radius 7

A) $x ^ { 2 } + y ^ { 2 } = \sqrt { 7 }$
B) $x ^ { 2 } + y ^ { 2 } = 7$
C) $x ^ { 2 } + y ^ { 2 } = 49$
D) $x ^ { 2 } + y ^ { 2 } = 14$