Reversible reactions and equilibrium — practice question

In the diagram, R shows one of the reactions in the Contact process. Which statement is correct?

• AGas Z is $\text{SO}_2$.
• BIn R, an iron catalyst speeds up the reaction.
• CIn R, the pressure is approximately $200\,\text{atm}$.
• DIn R, the temperature is approximately $45^{\circ}\text{C}$.