Which One of the Following Statements Is True

Which one of the following statements is true?

A) The activity method of computing depreciation could result in zero depreciation expense in some periods of time.
B) If the activity method is in use, residual value should not be subtracted from cost to determine the depreciation base.
C) The activity method produces a constant unit cost of depreciation.
D) The activity method should be used when the service life of the asset is affected mostly by the passage of time.