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. How much of depletion was capitalized as inventories in 2020?

a. 400,000

b. 450,000

c. 300,000

d. 540,000