The general solution of the differential equation $\frac{dy}{dx}+4x\, y^2 =0 $ is :

$y=\frac{1}{2x^2-C}, $ where C is a constant $y=2x^2-C,$ where C is a constant $y=x^2-C,$ where C is a constant $y=\frac{1}{x^2-C}, $ where C is a constant

$y=\frac{1}{2x^2-C}, $ where C is a constant