Bill is restoring a car and has already spent $$4000$ on the restoration. He expects to be able to sell the car for $$6300.$ Bill discovers that he needs to do an additional $$2400$ of work to make the car worth $$6300$ to potential buyers. He could also sell the car now, without completing the additional work, for $$3800.$ What should he do$?$

He should complete the additional work and sell the car for $$6300.$

He should sell the car now for $$3800.$

It does not matter if Bill sells the car now or completes the work and then sells it at the higher price because the outcome will be the same either way.

He should keep the car since it wouldn't be rational to spend $$6400$ restoring a car and then sell it for only $$6300.$