ANS:B - 0.3

A cupola is a type of furnace used for melting metals in foundries. It operates by burning coke, a type of fuel derived from coal, to generate heat. The coke is primarily used to provide the necessary heat to melt the metal charge placed in the cupola. The ratio of coke to metal is crucial in the operation of a cupola. While the exact amount of coke required can vary depending on factors such as the type of metal being melted, the efficiency of the cupola, and other process variables, a commonly used figure is around 0.3 tons of coke per ton of casting. This means that for every ton of metal produced in the cupola, approximately 0.3 tons of coke are consumed during the melting process. The coke provides the heat energy needed to raise the temperature of the metal charge to its melting point and sustain the molten state throughout the casting process.