The number of photons entering the pupil of our eye per second corresponding to the minimum intensity of white light that we humans can perceive . Take the area of the pupil to be about $0.4\;cm^2$ and the average frequency of white light to be found $6 \times 10^4 Hz$

Question

$\begin{array}{1 1} 10^4 s^{-1} \\ 10^3 s^{-1} \\ 10^2 s^{-1} \\ 10^8 s^{-1} \end{array}$