Properties of Indefinite Integrals

Consider the following statements regarding the integration of the function $4x^2+8x$.

I. The indefinite integral $\int (4x^2+8x) \,dx$ evaluates to $\frac{4x^3}{3}+ 4x^2+ C$.

II. The derivative of $\frac{4x^3}{3}+ 4x^2+ C$ with respect to $x$ is $4x^2+8x$.

III. The expression $4x^2+8x$ can be factored as $4x(x+2)$. Applying an appropriate substitution to this factored form will result in an antiderivative that differs from the one in statement I by only a constant.

Which of the statements above are true?