Which of the Following Is a Gas-Evolution Reaction

Which of the following is a gas-evolution reaction?

A) 2 C₂H₆(l) + 7 O₂(g) → 4 CO₂(g) + 6 H₂O(g)
B) 2 H₂(g) + O₂(g) → 2 H₂O(g)
C) KCl(aq) + NaNO₃(aq) → KNO₃(aq) + NaCl(s)
D) NH₄Br(aq) + KOH(aq) → KBr(aq) + NH₃(g) + H₂O(l)
E) None of the above is a gas-evolution reaction.