A unit positive point charge of mass m is projected with a velocity V inside the tunnel as tunnel as shown. The tunnel has been made inside a uniformly charged nonconducting sphere (charge density\[\rho \]). The minimum velocity with which the point charge should be projected such that it can reach the opposite end of the tunnel is equal to

• A. \[{{[\rho {{R}^{2}}/4m{{\varepsilon }_{0}}]}^{1/2}}\]
• B.             \[{{[\rho {{R}^{2}}/24m{{\varepsilon }_{0}}]}^{1/2}}\]
• C.             \[{{[\rho {{R}^{2}}/6m{{\varepsilon }_{0}}]}^{1/2}}\]
• D.             zero because the initial and the final points are        at some potential