During 2016, it cost Westa, Inc. $18 per unit to produce part T5. During 2017, it has increased to $21 per unit. In 2017, Southside Company has offered to provide Part T5 for $16 per unit to Westa. As it pertains to the make-or-buy decision, which statement is true?

Select one:

a. Differential costs are $5 per unit.

b. Incremental costs are $2 per unit.

c. Net relevant costs are $2 per unit.

d. Incremental revenues are $3 per unit.