The correct option is A They form ionic compounds
Elements try to become stable by attaining inert gas configuration. In this process, they either lose or gain electrons or share electron pairs. Atoms form positive ions when they lose electrons and upon gaining electrons, they form negative ions. A metal and a non-metal combine to form an Ionic compound by complete transfer of electrons from the metal to a non-metal. Example, in NaCl, Sodium loses one electron to Chlorine to form Sodium Chlorine.