Varcore Inc. is currently acquiring a key component from its sister company, Farcore Inc., at a transfer price of $$10$ per unit. Farcore's variable cost of purchasing the unit is $$4,$ and its fixed cost per unit is $$3$ per unit. Farcore does not have any excess capacity and can sell all it makes to external customers at $$10$ per unit. Varcore has been offered a price of $$9$ per unit for the component from another vendor and is insisting that Farcore reduce its price to $$9.$ Which of the following statements below is false regarding this scenario?

a$.$

The company will be better off if Farcore rejects Varcore's demand and instead sells the units that Varcore would buy to outside customers.

b$.$

Since Farcore is operating at full capacity and has other external customers ready to purchase additional units, the best transfer price is its regular market price.

c$.$

Varcore should purchase the unit externally because the internal cost of purchasing the unit internally is a variable cost of $$4$ per unit plus an opportunity cost of $$6$ per unit, or $$10.$

d$.$

Varcore should not accept the outside offer because the variable cost of purchasing it inside is only $$4$ per unit.