$\int \frac{\left(\cos x-x \sin x+3 x^{2}\right)}{x \cos x+x^{3}} d x=$ কত?

$\frac{\sin x+x \cos x}{x \sin x+3 x}+c$

$\log \left(x^{3}+x \cos x\right)+c$

$\log \left(\frac{\sin x+x \cos x}{x^{2}+x \sin x}\right)+c$

$\log \left(\frac{\sin x+x \cos x}{x^{2}+x \sin x}\right)$