A man can throw a stone 80 m. The maximum height to which he can raise the stone is

The correct option is D 40 m
$R_{max}=\frac{u^2}{g}=80m[for\theta ={45}^{\circ }]$
But height can be maximum when body projected vertically up
$H_{max}=\frac{u^{2}si{n}^2{90}^{\circ }}{2g}=\frac{u^2}{2g}=\frac{1}{2}\left(\frac{u^2}{g}\right)=40m$