The cost to produce Part A was $37 per unit in 2021. During 2022, it increased to $40 per unit. In 2022. Sheritan Company has offered to supply Part A for $25 per unit. No fixed costs are avoidable. For the make-or-buy decision, differential costs are $15 per unit. incremental costs are $3 per unit. incremental revenues are $15 per unit. net relevant costs are $3 per unit