The cathode of a photocell is changed such that the work function changes from $w_1$ to $w_2$ $(w_2 > w_1)$. If the saturation currents before and after the change are $I_1$ and $I_2$ respectively,and all other conditions (such as incident light intensity and frequency) remain unchanged,then (assuming $h\nu > w_2$):

• A
  $I_1 = I_2$
• B
  $I_1 < I_2$
• C
  $I_1 > I_2$
• D
  $I_1 < I_2 < 2I_1$