The correct answer is B. depreciation.
Depreciation is the allocation of the cost of an asset over its useful life. It is a way of accounting for the fact that assets lose value over time, due to wear and tear, obsolescence, or other factors.
Appreciation is the opposite of depreciation. It is an increase in the value of an asset over time. Appreciation can occur for a number of reasons, such as inflation, changes in market conditions, or improvements to the asset.
Assets are items that a company owns and uses in its business. They can be tangible, such as buildings and equipment, or intangible, such as patents and trademarks.
Liabilities are debts that a company owes to others. They can be short-term, such as accounts payable, or long-term, such as bonds.
In conclusion, the purchase cost of assets over its useful life is classified as depreciation. This is because depreciation is a way of accounting for the fact that assets lose value over time.