Please hurry I’m on a timed quiz

Which formula equation shows a reversible reaction?
O 2Na+F₂ → 2NaF
O CaCO,→CaO+CO,
O NH₂Cl(s) → NH3(g) + HCl(g)
O 2H₂O₂(aq)2H₂O(l) + O₂(g)