The correct answer is options (i) and (iv).Concept:Corrosion: The eating away of the surface of metals due to the action of air, moisture, or chemicals is called corrosion. Explanation:The rusting of iron can be prevented by painting, oiling, greasing, galvanizing, chrome plating, anodizing, or making alloys.Galvanization: It is a method of protecting steel and iron from rusting by coating them with a thin layer of zinc.Alloying: An alloy is a homogeneous mixture of two or more metals, or a metal and a non-metal. When iron is mixed with nickel and chromium, we getstainless steel, which is hard and does not rust.Anodising: It is an electrolytic process in which a layer of oxide is formed on the metal surface making it resistant to further corrosion.Painting, oiling, and greasing form a protective film between air and the surface of iron protecting it from corrosion. Additional InformationSoldering: It is a joining process used to join different types of metals together by melting solder.Solder is an alloy usually made of tin and lead.Thermit reaction: The displacement reaction between iron oxide and aluminum releasing a lot of heat is called the thermit reaction.It is used to join railway tracks or cracked machine parts. Carbonization: The dead plants and vegetation due to temperature and high pressure over hundreds of years slowly turned into coal.This slow conversion of dead plants and forests into coal is called the process of carbonization.