Prince George Mining provides the following information about their diamond mine. The annual depletion expense is $450,000 and there were 1,000,000 units extracted and sold during the year. The total estimated units of production is 16,000,000 and the residual value is estimated to be $500,000. Determine the depletion base is for the resource. Select answer from the options below $35,555,555 $7,700,000 $7,200,000 $15,500,000