All of the following could explain the difference between the accounting treatment for depreciation and cost depletion except O a. the cost of the asset is the starting point from which computation of the amount of the periodic charge is made to operations for depreciation, but the fair value reassessed each year as the starting point for the periodic charge for depletion O b. many formulas are used in computing depreciation but only one is used to any extent in computing depletion O c. depletion applies to natural resources while depreciation applies to plant and equipment O d. depletion refers to the physical exhaustion or consumption of the asset while depreciation refers to the wear, tear, and obsolescence of the asset