Which of the following statements concerning depreciation expense is most correct?

a. Depreciation expense accounts for the loss of value of inventory.

b. Depreciation expense accounts for the loss of value of securities investments.

c. Depreciation expense accounts for the loss of value of fixed assets (property and equipment).

d. For accounting purposes, depreciation expense is calculated by the double declining balance method.

e. For accounting purposes, depreciation expense is calculated by the triple declining balance method.