The figure shows the variation of photocurrent with anode potential for a photo-sensitive surface for three different radiations. Let $I_a$, $I_b$ and $I_c$ be the intensities and $f_a$, $f_b$ and $f_c$ be the frequencies for the curves $a$, $b$ and $c$ respectively 

In a photoelectric graph, the saturation photocurrent depends on intensity, while the stopping potential depends on frequency. From the figure, curves $a$ and $b$ reach different saturation currents, so their intensities are different. Also, curves $a$ and $b$ start rising from the same stopping-potential side, which means their stopping potentials are equal. Hence their frequencies are equal. Therefore, $f_a=f_b$ and $I_a\ne I_b$. Now comparing with the given options, this matches option $A$.