The fixed assets of a $10-$year project cost $$600,000,$ which will be depreciated using $10-$year straight$-$line method. At the end of the project, the asset can be sold for $$50,000.$ If the tax rate is $20\%,$ how much is the book value after $10$ years?

$$55,000$

$$60,000$

$$48,000$

$$9,000$

$$50,000$