ANS:B - 3

The volume of blast furnace slag is about 3 times the volume of hot metal (pig iron) of the same weight. During the iron smelting process in a blast furnace, various impurities present in the iron ore combine with limestone to form slag. Slag is lighter than molten iron and floats on its surface. Once the molten iron (pig iron) is tapped from the blast furnace, the slag is also removed. The volume of slag produced is typically about three times the volume of the molten iron, although this can vary depending on factors such as the composition of the raw materials and the operating conditions of the blast furnace.