The answer is (3) hydrogen bonding. This is a question of intermolecular forces. H2O is highly polar (the O—H bond is particularly polar since O is so electronegative), and CH4 is about as nonpolar as it gets. So, while H2O molecules are held together by relatively strong hydrogen bonds (which, keep in mind, are not actually bonds), CH4 molecules are held together by much weaker London dispersion/Van der Waals forces. Thus, it takes more thermal energy to separate H2O molecules, and H2O therefore has a higher boiling point.
