13. When using PP&E as the forecast driver for depreciation, which of the following is most accurate? a) From both an ideal and a practical standpoint, the driver should be net PP&E. b) From both an ideal and a practical standpoint, the driver should be gross PP&E. c) Ideally, the driver should be net PP&E, but practically the driver should be gross PP&E. d) Ideally, the driver should be gross PP&E, but practically the driver should be net PP&E