Photoelectric emission takes place from a certain metal at threshold frequency $\nu$. If the radiation of frequency $2\nu$ is incident on the metal plate, the maximum velocity of the emitted photoelectron will be ($m = \text{mass of electron}$, $h = \text{Planck's constant}$)

• A
  $\sqrt{\frac{2h\nu}{m}}$
• B
  $\sqrt{\frac{h\nu}{2m}}$
• C
  $\sqrt{\frac{h\nu}{3m}}$
• D
  $\sqrt{\frac{h\nu}{m}}$