Factor completely:

X^3 (3)(x^2+1)^2 (2x)+(x^2+1)^3 (3x^2)

Please help. I have tried multiple times.

x^3 (3)(x^2+1)^2 (2x)+(x^2+1)^3 (3x^2)

6x^4(x^2+1)^2 + 3x^2(x^2+1)^3
3x^2(x^2+1)^2 (2x^2+x^2+1)
3x^2(x^2+1)^2 (3x^2+1)