Which one is an example of heterogeneous catalysis?

The number of correct statements about modern adsorption theory of heterogeneous catalysis from the following is ..........
$A.$ The catalyst is diffused over the surface of reactants.
$B.$ Reactants are adsorbed on the surface of the catalyst.
$C.$ Occurrence of chemical reaction on the catalyst's surface through formation of an intermediate.
$D.$ It is a combination of intermediate compound formation theory and the old adsorption theory.
$E.$ It explains the action of the catalyst as well as those of catalytic promoters and poisons.

The term $Platforming$ is:

In aqueous solution,$Na_2SO_3$ is oxidized by air,but $Na_3AsO_3$ is not. However,when air is passed through a solution containing both $Na_2SO_3$ and $Na_3AsO_3$,both are oxidized. This is an example of:

Which one of the following acts as an autocatalyst during the titration of $KMnO_4$ and oxalic acid in the presence of dilute $H_2SO_4$?

Give information about Homogeneous catalysis and Heterogeneous catalysis.