Solve the Differential Equation $$x y ^ { \prime } + 4 y = \frac { \cos x } { x ^ { 3 } } , x > 0$$

Multiple Choice

Solve the differential equation.
- $$x y ^ { \prime } + 4 y = \frac { \cos x } { x ^ { 3 } } , x > 0$$

A) $y = \frac { \cos x + C } { x ^ { 3 } } , x > 0$
B) $y = \frac { \cos x + C } { x ^ { 4 } } , x > 0$
C) $y = \frac { \sin x + C } { x ^ { 3 } } , x > 0$
D) $y = \frac { \sin x + C } { x ^ { 4 } } , x > 0$