A particle of mass m is thrown upwards from the surface of the earth, with a velocity u. The mass and the radius of the earth are respectively, M and R. G is gravitational constant and g is acceleration due to gravity on the surface of the earth. The minimum value of u so that the particle does not return back to earth, is :

• A

  $\sqrt{\frac{2\mathrm{GM}}{{\mathrm{R}}^2}}$

• B

  $\sqrt{\frac{2\mathrm{GM}}{\mathrm{R}}}$

• C

  $\sqrt{\frac{2\mathrm{gM}}{{\mathrm{R}}^2}}$

• D

  $\sqrt{2{\mathrm{gR}}^2}$