Solve the Problem $f ( x , y ) = \sqrt { x ^ { 2 } + y ^ { 2 } }$

Multiple Choice

Solve the problem.
-Find an equation for the level curve of the function $f ( x , y ) = \sqrt { x ^ { 2 } + y ^ { 2 } }$ that passes through the point $( 3,4 )$ .

A) $x ^ { 2 } + y ^ { 2 } = 7$
B) $x + y = 5$
C) $x ^ { 2 } + y ^ { 2 } = 25$
D) $x ^ { 2 } + y ^ { 2 } = 5$