The equilibrium constant will be very large because that reaction will be very, very close to going to completion, which means that you'll have significantly more product than reactants at equilibrium.
By definition, the equilibrium constant will be
Essentially, the hydrogen will react completely with oxygen. By comparison, the amounts of reactants left will be insignificant compared with the amount of water formed.
If you get much more product than reactants at equilibrium,
The most suitable answer is