During $2020,$ Logan Corporation acquired a mineral mine for $$4,000,000$ of which $$400,000$ was ascribed to land value after the mineral has been removed. Geological surveys have indicated that $10$ million units of the mineral could be extracted. During $2020,1,500,000$ units were extracted and $1,250,000$ units were sold. What is the amount of depletion expensed for $2020?$

$$540,000$

$$450,000$

$$400,000$

$$300,000$