Answer
(b) The photocurrent is proportional to the light intensity
Work Step by Step
According to classical electromagnetic wave theory of light, energy of light is spread uniformly over all the electrons present on the surface of object.
Classical wave theory says that intensity of light is directly proportional to the square of electric field vector $\overrightarrow{E}$.
Therefore, increasing intensity of light will increase the amplitude of electric field vector $\overrightarrow{E}$.
Since the force that incident light exerts on an electron is e$\overrightarrow{E}$, the theory predicts more intensity means more pulling force on electron hence more photocurrent.
