1 Heritage Company manufactures a beautiful bookcase that enjoys widespread popularity. The company has indefinitely at the plant's full capacity of 4,000 bookcases per year. You are required to classify following cost item: Indirect materials, factory... $18,000 O Variable cost, indirect cost, overhead cost, product cost Variable cost, direct cost, overhead cost, product cost Variable cost, indirect cost, overhead cost, period cost Variable cost, indirect cost, prime cost, product cost