Which one is an example of heterogenous catalysis?

Pumice stone is an example of -

Shown below are adsorption isotherms for a gas 'X' at temperatures T₁, T₂ and T₃ :

p and $${x \over m}$$ represent pressure and extent of adsorption, respectively. The correct order of temperatures for the given adsorption is :

Given below ae two statements

Statement I:

In the coagulation of a negative sol, the flocculating power of the three given ions is in the order Al³⁺ > Ba²⁺ > Na⁺

Statement II:

In the coagulation of a positive sol, the flocculating power of the three given salts is in the order NaCl > Na₂SO₄ > Na₃PO₄

In the light of the above statements, choose the most appropriate answer from the options given below