The escape velocity of an object from the earth depends upon the mass of earth (M), its mean density ( $p$ ), its radius
(R) and gravitational constant (G), thus the formula for escape velocity is
(A) $U=\mathrm{R} \sqrt{[}(8 \pi / 3) \mathrm{Gp}]$
(C) $\mathrm{U}=\sqrt{(2 \mathrm{GMR})}$
(D) $U=\sqrt{\left[(2 \mathrm{GMR}) / \mathrm{R}^{2}\right]}$