Iron reacts with steam to form hydrogen and an iron oxide. $3\text{Fe(s)} + 4\text{H}_2\text{O(g)} \rightleftharpoons \text{Fe}_3\text{O}_4\text{(s)} + 4\text{H}_2\text{(g)}$ All four substances are present in a system at equilibrium. Which changes would reduce the mass of Fe present at equilibrium?
- A1, 2 and 3
- B1 and 2 only
- C2 and 3 only
- D1 only