Why does hydrogen occur in a diatomic form rather than in a monoatomic form under normal conditions?

Options

1. ABecause the ionization enthalpy of hydrogen atom is very high, hence, it is very hard to remove its only elect
2. BBecause hydrogen has an odd number of electrons, leading to the formation of H 2 molecules.
3. CBecause the diatomic form of hydrogen has a lower energy state than the monoatomic form.
4. DBecause hydrogen's atomic size allows it to readily form H 2 molecules through van der Waals forces.