Final answer:
Hydrogen forms the least polar bond with hydrogen out of the given options.
Step-by-step explanation:
When examining electronegativity values, the atom that will form the least polar bond with hydrogen (H) is hydrogen itself (option a). Hydrogen has an electronegativity value of 2.1, which is the same as that of fluorine (Fl) and lower than chlorine (Cl) and bromine (Br). The difference in electronegativity values between hydrogen and any of these atoms is negligible, resulting in a nonpolar bond.