The Weber Company purchased a mining site for $500,000 on July 1, 2009. The company expects to mine ore for the next 10 years and anticipates that a total of 100,000 tons will be recovered. The estimated residual value of the property is $80,000. During 2009, the company extracted and sold 4,000 tons of ore. The depletion expense for 2009 is:
a. $16,800
b. $43,200
c. $20,000
d. $10,500