The correct answer is D.
Depreciation is an accounting process that allocates the cost of a long-lived asset to expense over its useful life. This is done in order to match the cost of the asset with the revenue that it generates.
Option A is incorrect because depreciation is not a process of asset valuation. Asset valuation is the process of determining the fair market value of an asset. Depreciation is a process of allocating the cost of an asset to expense over its useful life.
Option B is incorrect because depreciation applies to both long-lived tangible assets and long-lived intangible assets. Tangible assets are assets that have physical substance, such as land, buildings, and equipment. Intangible assets are assets that do not have physical substance, such as patents, trademarks, and goodwill.
Option C is incorrect because depreciation is not used to indicate a decline in the market value of a long-life asset. Depreciation is used to allocate the cost of an asset to expense over its useful life. The market value of an asset may decline over time, but this is not the reason for depreciation.
I hope this helps!