Solve the equation.

$(x+9x{y}^4)dx+e^{x^2}{y}^{3}dy=0$

Begin by separating the variables. Choose the correct answer below.

A$.\frac{y^3}{1+9y^4}dx=-\frac{x}{e^{x^2}}dy$

B$.\frac{y^3}{1+9y^4}dy=-\frac{x}{e^{x^2}}dx$

C$.\frac{dy}{dx}=-\frac{x+9x{y}^4}{e^{x^2}{y}^3}$

D$.$ The equation is already separated.

An implicit solution in the form $F(x,y)=C$ is $=C,$ where $C$ is an arbitrary constant.

$($Type an expression using $x$ and $y$ as the variables.$)$