Write the Equation of a Circle with the Given Center $x ^ { 2 } - y ^ { 2 } = 7$

Multiple Choice

Write the equation of a circle with the given center and radius.
-Center at (0, 0) ; Radius 7

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