Which of the folowing best descrbes how the constant gross - margin percentage NRV method allocates joint costs? A. a gross margin is calculated and for each product and then gross margin is deducted along trom the final sales value of a product to dotive the joint cost allocanion for a product. B. a gross margin is calculated and for each product and then the gross margin is deducted along with separable costa from the final sales value of a product to derive the jaint cost alocation tor a product C. an overall gross margin is cavculabed and fot each product the gross margin is deducted along with separable costs from the final sales value of a product to derive the joint cost allocafion tor the product D. an oversl gross margin is calculated and for each product and then the gross magin is deducted aloog wih separable costs form the final sales value of all the products produced in the joint processing and the allocationl are then made based on physical volume measures