Option A is correct because the context demonstrates that iron participates in displacement reactions. The textbook shows that iron displaces copper from copper sulphate solution in the reaction Fe + CuSO₄ → FeSO₄ + Cu. Additionally, the balanced equation 3Fe + 4H₂O → Fe₃O₄ + 4H₂ indicates that iron can produce hydrogen gas when it reacts. Activity 1.3 mentions that adding dilute hydrochloric acid to metal granules (zinc) results in observations like evolution of a gas. Following this pattern, when dilute hydrochloric acid is added to iron fillings, iron displaces hydrogen from the acid, producing hydrogen gas and iron chloride.