Photons of wavelength $\lambda$ emitted by a source of power $P$ are incident on a photocell. If the current produced in the cell is $I$,then the percentage of incident photons which produce current in the photocell is: (where $h$ is Planck's constant and $c$ is the speed of light in vacuum)

• A
  $\frac{100 e P c}{I h \lambda}$
• B
  $\frac{100 I h c}{e P \lambda}$
• C
  $\frac{100 I h \lambda}{e P c}$
• D
  $\frac{100 e P \lambda}{I h c}$