can somebody explain it to me please?

Range be R and height be h
[tex]\boxed{\sf R=\dfrac{u^2sin2\theta}{g}}[/tex]
[tex]\boxed{\sf h=\dfrac{u^2sin^2\theta}{2g}}[/tex]
u=initial velocity
theta is angle of projection.
g=acceleration due to gravity
ATQ
[tex]\\ \sf\longmapsto R=2h[/tex]
[tex]\\ \sf\longmapsto \dfrac{u^2sin2\theta}{g}=\dfrac{2u^2sin^2\theta}{2g}[/tex]
Cancelling required ones
[tex]\\ \sf\longmapsto sin^2\theta=sin2\theta[/tex]
sin2O=2sinOcosO
[tex]\\ \sf\longmapsto sin^2\theta=2sin\theta cos\theta [/tex]
[tex]\\ \sf\longmapsto \dfrac{sin^2\theta}{sin\theta cos\theta=2[/tex]
[tex]\\ \sf\longmapsto \dfrac{sin\theta}{cos\theta}=2[/tex]
[tex]\\ \sf\longmapsto tan\theta=2[/tex]
[tex]\\ \sf\longmapsto \theta=tan^{-1}(2)[/tex]
[tex]\\ \sf\longmapsto \theta=63.4°[/tex]
Done
Option B is correct