In Langmuir treatment of adsorption,_________________?

A. Whole surface of the catalyst does not have the same activity for adsorption and there is
attraction between the adsorbed molecule
B. Whole surface of the catalyst is essentially uniform and the adsorbed molecule has no effect
on the rate of adsorption per site
C. All the adsorption does not take place by the same mechanism
D. Extent of adsorption is more than one complete monomolecular layer on the surface