The correct answer is: Wrought iron.
Wrought iron is the purest form of iron. It is made by repeatedly heating and hammering pig iron until the impurities are removed. Wrought iron is a soft, ductile metal that is easily worked and welded. It is used in a variety of applications, including making nails, chains, and other hardware.
Cast iron is a type of iron that is made by melting pig iron and pouring it into a mold. Cast iron is a hard, brittle metal that is not easily worked. It is used in a variety of applications, including making cookware, engine blocks, and other castings.
Mild steel is a type of steel that is made by adding a small amount of carbon to iron. Mild steel is a strong, ductile metal that is easily worked. It is used in a variety of applications, including making beams, plates, and other structural components.
High carbon steel is a type of steel that is made by adding a large amount of carbon to iron. High carbon steel is a hard, strong metal that is not easily worked. It is used in a variety of applications, including making tools, knives, and other cutting tools.