$\int x^{2}$$\left[1+\ln \left(x^{3}+1\right)\right]$$d x= ?$

$\left(x^{3}+1\right) \ln \left(x^{3}+1\right)$

$\frac{1}{3}\left(x^{3}+1\right) \ln \left(x^{3}+1\right)$

$\frac{x^{3}+1}{\ln \left(x^{3}+1\right)}$

$\frac{3\left(x^{3}+1\right)}{\ln \left(x^{3}+1\right)}$