The file P02_46.xlsx contains data on prices of products for several of a chain store’s locations, a discount schedule offered to customers depending on how much they spend, and commission rates of the sales-people at the various stores. Your job is to develop an invoice form. Specifically, you should enter formulas in the gray cells so that whenever data are entered in the blue cells, the formulas in the gray cells calculate automatically. As an extra, use data validation in cell B23 so that the user can choose a city from a list of cities where the chain has its stores.