Which of the following function is an odd function?

$\mathrm{f}\left(\mathrm{x}\right)={\mathrm{x}}^2 \mathrm{f}:\mathrm{R}\to \mathrm{R}$

$f\left(x\right) = x^2 f : R^{+} -> R$

$\mathrm{f}\left(\mathrm{x}\right)={\mathrm{x}}^2 \mathrm{f}:{\mathrm{R}}^{+}\to {\mathrm{R}}^{+}$