Concept:Petrol and kerosene are joint products obtained from the same crude oil refining process.Explanation:An increase in the supply of petrol means producers are refining more crude oil.Since kerosene is produced alongside petrol from the same crude oil, the quantity of kerosene obtained will also rise.Thus, the supply of petrol and the supply of kerosene move in the same direction.The cost of crude oil production is not directly relevant here, and it would not lower kerosene supply in this situation.Answer:B. supply of kerosene will rise