Goldmine Mining Company purchased a mine in 2018 for $3,400,000. It was estimated that the mine contained 200,000 tons of ore and that the mine would be worthless after all of the ore was extracted. The company extracted 25,000 tons of ore in 2018 and 30,000 tons of ore in 2019. What is the amortization expense for 2020?

a) $425,000

b) $680,000

c) $340,000

d) $510,000