Duralumin is a type of aluminum alloy that is made by mixing aluminum with copper and another metal. The options given are zinc and gold, lead and manganese, nickel and silver, and manganese and magnesium. Among these options, the correct one is manganese and magnesium. Therefore, duralumin consists of aluminum, copper, manganese, and magnesium. This alloy is known for its strength, hardness, and durability, and is commonly used in the manufacturing of aircraft and other high-stress applications.