A student investigating a gas-phase catalytic process for converting sulfur dioxide to sulfur trioxide proposes the following elementary steps.

Step 1 (fast): \(2\text{NO}\text{(g)} \rightleftharpoons \text{N}_2\text{O}_2\text{(g)}\)

Step 2 (slow): \(\text{N}_2\text{O}_2\text{(g)}+\text{O}_2\text{(g)} \rightarrow 2\text{NO}_2\text{(g)}\)

Step 3 (fast): \(\text{NO}_2\text{(g)}+\text{SO}_2\text{(g)} \rightarrow \text{NO}\text{(g)}+\text{SO}_3\text{(g)}\)

Which choice correctly identifies the catalyst and all the reaction intermediates in the proposed mechanism?