Barkley Company Currently Makes a Product Internally,but Is Considering Outsourcing

Barkley Company currently makes a product internally,but is considering outsourcing production.Barkley rents a special machine used to make the product,and would no longer need this machine if the part is outsourced.The rent on the machine is what type of cost for this make-or-buy decision?

A) sunk and not differential.
B) avoidable and differential.
C) unavoidable and differential.
D) avoidable and not differential.
E) None of the answer choices is correct.