Match the catalysts (Column I) with products (Column II)

We start by recalling the industrial reactions in which each given catalyst is characteristically employed.

For A we have $$\text{V}_2\text{O}_5$$, vanadium(V) oxide. This substance is the classical catalyst in the Contact Process where sulphur dioxide is oxidised to sulphur trioxide: $$\text{SO}_2+\dfrac12\text{O}_2 \xrightarrow{\text{V}_2\text{O}_5} \text{SO}_3$$ The $$\text{SO}_3$$ is then absorbed in water to give sulphuric acid $$\text{H}_2\text{SO}_4$$. Hence the final product associated with $$\text{V}_2\text{O}_5$$ is $$\text{H}_2\text{SO}_4$$, which is entry R.

For B we have the pair $$\text{TiCl}_4/\text{Al(Me)}_3$$. This pair is known as the Ziegler-Natta catalyst. The well-known use of this catalyst is the polymerisation of ethene ($$\text{CH}_2= \text{CH}_2$$) to polyethene: $$n\,\text{CH}_2=\text{CH}_2 \xrightarrow[\text{pressure}]{\text{TiCl}_4/\text{Al(Me)}_3} (-\text{CH}_2-\text{CH}_2-)_n$$ Polyethene is called polyethylene, which is entry P.

For C we are given $$\text{PdCl}_2$$, palladium(II) chloride. This salt is used in the Wacker oxidation, in which ethene is converted into acetaldehyde (ethanal): $$\text{CH}_2=\text{CH}_2 + \dfrac12\text{O}_2 + \text{H}_2\text{O} \xrightarrow{\text{PdCl}_2/\text{CuCl}_2} \text{CH}_3\text{CHO}$$ The product $$\text{CH}_3\text{CHO}$$ is ethanal, entry Q.

For D we have iron oxide, usually $$\text{Fe}_2\text{O}_3$$ promoted with $$\text{K}_2\text{O}$$ and $$\text{Al}_2\text{O}_3$$, the heterogeneous catalyst in the Haber process: $$\dfrac12 \text{N}_2 + \dfrac32 \text{H}_2 \xrightarrow[\text{200 atm},\,500^\circ\text{C}]{\text{Fe}_2\text{O}_3\,(K_2\text{O},Al_2\text{O}_3}) \text{NH}_3$$ The resulting product is ammonia $$\text{NH}_3$$, entry S.

Collecting the matches we have
A - R,  B - P,  C - Q,  D - S.

Comparing with the given options, this exact sequence corresponds to Option D.

Hence, the correct answer is Option D.