Solve the Differential Equation $$36 y ^ {tt } + y = 0$$

Multiple Choice

Solve the differential equation. $$36 y ^ {tt } + y = 0$$

A) $y ( x ) = c _ { 1 } \cos ( - 6 x ) + c _ { 2 } \sin ( - 6 x )$
B) $y ( x ) = c _ { 1 } \cos \left( - \frac { x } { 36 } \right) + c _ { 2 } \sin \left( - \frac { x } { 6 } \right)$
C) $y ( x ) = c _ { 1 } \cos \left( \frac { x } { 6 } \right) + c _ { 2 } \sin \left( \frac { x } { 6 } \right)$
D) $y ( x ) = c _ { 1 } \cos ( 6 x ) + c _ { 2 } \sin ( 6 x )$
E) $y ( x ) = c _ { 1 } \cos ( 36 x ) - c _ { 2 } \sin ( 36 x )$