According to Freundlich adsorption isotherm, which of the following is correct?

Question

(a) $\frac{x}{m} \propto p^1$

(b) $\frac{x}{m} \propto p^{\frac{1}{n}}$

(c) $\frac{x}{m} \propto p^0$

(d) All the above are correct for different ranges of pressure.