During 2019 , it cost King, Inc. $12 per unit to produce part T5. During 2020 , it has increased to $15 per unit. In 2020, Miller Company has offered to provide Part T5 for $11 per unit to King. As it pertains to the make-or-buy decision, which statement is true? Incremental costs are $3 per unit. Incremental revenues are $1 per unit. Net relevant costs are $3 per unit. Differential costs are $4 per unit