The correct answer is D. 18th or zero group.
The inert gases are also known as noble gases. They are the elements in group 18 of the periodic table. They are all gases at room temperature and pressure. They are very unreactive and do not form compounds easily.
The alkali metals are the elements in group 1 of the periodic table. They are all metals and are very reactive. They form compounds easily and are often used in batteries.
The 16th group is the oxygen group. It contains the elements oxygen, sulfur, selenium, tellurium, and polonium. These elements are all non-metals and are very reactive. They form compounds easily and are often used in industrial processes.
The halogen group is the 17th group of the periodic table. It contains the elements fluorine, chlorine, bromine, iodine, and astatine. These elements are all non-metals and are very reactive. They form compounds easily and are often used in industrial processes.