Copeland Inc. produces product X-547 in a joint manufacturing process. The company is studying whether to sell X-547 at the split-off point or upgrade (i.e., further process) the product to become Xylene. The following information has been gathered:

1. (1) Selling price per pound of X-547.
2. (2) Variable manufacturing costs of the upgrade process.
3. (3) Avoidable fixed costs of the upgrade process.
4. (4) Selling price per pound of Xylene.
5. (5) Joint manufacturing costs to produce X-547.

Which of the items should be reviewed when making the upgrade decision?