From this figure describing photoelectric effect, we may infer correctly that :

Question

$\begin {array} {1 1} (A)\;\text{$Na$ and $Al$ both have same threshold frequency}\\ (B)\;\text{maximum $K.E$ for both the metals depend linearly on the frequency} \\ (C)\;\text{the stopping potentials are different for $Na$ and $Al$ for the same change in frequency} \\ (D)\;\text{$Al$ is a more photosensitive material than $Na$} \end {array}$