I need help so what is it?

c) Forming hydrogen-oxygen bonds gives off energy.

Explanation:

a and b cannot be the answers because bond breaking is an endothermic process, it takes in energy. It is bond forming that gives out energy. It is worth noting that even exothermic reactions like this one do take in energy to break the bonds of the reactants first. It is just that the energy they take in is less than the energy they give out during bond formation and that is why the net result is that they are exothermic.