The correct options are
H3 : Hydrogen has 1 electron in its outer layer. So 2 Hydrogen could bond and the result is a new H2 which has a 2-electron in its covalent bond. If you want to add another H to this H2 the new electron can not be stable on the same layer.
H−He: Helium is a stable atom, so the tendency to form a molecule with Hydrogen will be very less.
He2: It is unstable as a molecule as it already has a fully filled orbital as a single helium atom. So there is no need of forming a molecule.
H3O: Oxygen just has two unpaired electrons and needs two more to complete its octet. One hydrogen needs one electron to make itself stable. So, here a total of three electrons are required to make the molecule stable, but Oxygen just has two. So, all the hydrogen can not be stabilized.