The correct answer is A. Depletion method.
Depletion is a method of accounting for the consumption of natural resources. It is a process of allocating the cost of a natural resource to the periods in which it is used. The depletion expense is calculated by multiplying the unit cost of the resource by the number of units extracted during the period.
The depletion method is the best method to account for the consumption of natural resources because it is based on the principle of matching costs with revenues. The depletion expense is matched with the revenue from the sale of the extracted resources. This provides a more accurate picture of the company’s profitability.
The revaluation method is not a depreciation method. It is a method of accounting for changes in the value of assets. The revaluation method is not appropriate for natural resources because the value of natural resources is not subject to significant changes.
The annuity method is a method of accounting for the amortization of intangible assets. It is not appropriate for natural resources because natural resources are not intangible assets.
Therefore, the best depreciation method in case of mineral deposit is the depletion method.