Differential equation associated with primitive y = Ae3x + Be5x :

$\frac{d^2 y}{d x^2}-8 \frac{d y}{d x}+15 y=0$

$\frac{d^2 y}{d x^2}+8 \frac{d y}{d x}-15 y=0$

$\frac{d^2 y}{d x^2}+8 \frac{d y}{d x}+y=0$

none of these