The correct answer is D. all of above.
A joint product is a product that is produced along with another product during the same production process. The main product is the product that is produced in the greatest quantity or that has the highest sales value. A product is any output that has total positive sales.
For example, when oil is refined, it produces several products, including gasoline, diesel fuel, and jet fuel. Gasoline is the main product, while diesel fuel and jet fuel are joint products. All of these products have total positive sales, so they are all products.
In another example, a bakery might produce bread, rolls, and pastries. Bread is the main product, while rolls and pastries are joint products. All of these products have total positive sales, so they are all products.