During $2021,$ it cost Coronado Inc. $\backslash$$$13$ per unit to produce Part T$5.$ During $2022,$ the cost has increased to $\backslash (\backslash$$ $14\backslash )$ per unit. In $2022,$ Wildhorse Company has offered to sell the Part T$5$ for $\backslash$$$8$ per unit to Coronado. With regard to the make$-$or$-$buy decision, which statement is true?

Incremental revenues are $\backslash$$$1$ per unit.

Incremental costs are $\backslash$$$5$ per unit.

Net relevant costs are $\backslash (\backslash$$ $5\backslash )$ per unit.

Differential costs are $\backslash (\backslash$$ $6\backslash )$ per unit.