The maximum velocity of the photoelectron emitted by the metal surface is $v$. The charge and mass of the photoelectron are denoted by $e$ and $m$ respectively. The stopping potential in volts is:

• A
  $\frac{v^{2}}{(m/e)}$
• B
  $\frac{v^{2}}{(e/m)}$
• C
  $\frac{v^{2}}{2(m/e)}$
• D
  $\frac{v^{2}}{2(e/m)}$