With an explanation please

Deming & Sons manufactures four grades of lubricant, W-10, W-20, W-30, and W-40, from a joint process. Additional information follows If Processed Further Units Product Produced 54,600 39,000 31,200 31,200 156,000 Sales Value at Split-Off $324,000 279,000 189,000 144,000 Additional CostsSales Values W-10 W-20 W-30 W-40 35,000 27,900 18,900 11,700 S 93,500 $355,000 324,000 234,000 156,000 $1,069,000 $936,000 Required Which, if any, of the four products would you recommend Deming & Sons sell at split-off (and not process further)? W-20 W-30 W-40 None of the products