On April 1, 2019, Justin Company Purchased a Copper Mine

On April 1, 2019, Justin Company purchased a copper mine at a cost of $28,000,000. The mine was estimated to contain 1,000,000 tons of ore and to have a residual value of $8,000,000 after mining operations are completed. During the year, 250,000 tons of ore were removed from the mine.
On December 31, 2019, the book value of the mine is:

A) $20,500,000
B) $23,000,000
C) $17,500,000
D) $14,000,000