Maximum velocity of the photoelectrons emitted by a metal surface is $1.2 \times 10^6 m/s$. Assuming the specific charge of the electron to be $1.8 \times 10^{11}C/kg$, the value of the stopping potential is

Question

$\begin {array} {1 1} (a)\;2\: V & \quad (b)\;3\: V \\ (c)\;4\: V & \quad (d)\;6\: V \end {array}$