If a photon has velocity c and energy E, then which of following represents its wavelength?

• A

  $\frac{\mathrm{hc}}{\mathrm{E}}$

• B

  $\frac{\mathrm{hv}}{\mathrm{c}}$

• C

  $\frac{\mathrm{hc}}{{\mathrm{c}}^2}$

• D

  hv