It is profitable to continue processing a joint product after the split-off point so long as

a. the incremental revenue from such processing exceeds the incremental processing costs incurred after the split-off point.

b. the incremental revenue from such processing exceeds the incremental processing costs incurred before the split-off point.

c. the incremental revenue from such processing exceeds the allocated joint costs attributable to the product.

d. the incremental revenue from such processing exceeds the sum of the allocated joint costs attributable to the product and the incremental processing costs incurred after the split-off point.