Books and brew (bb) is a large city bookstore that sells books and music cd's, and also has a cafe. Currently, bb uses a single-driver system to allocate its operating costs to each of its three product lines, using the the number of items sold as the single cost driver. But bb's management is concerned that this allocation system may not be providing the best information for making a variety of pricing decisions. Bb's operating costs for 2017 were as follows: