Which of the following is true about the MACRS depreciation system? a. No salvage value is used before depreciation percentages are applied to depreciable real estate. b. No matter when equipment is purchased during the month, it is considered to have been purchased mid-month for MACRS depreciation purposes. c. Residential rental buildings are depreciated straight-line over 20 years. d. Commercial real estate buildings are depreciated over 39 years using accelerated depreciation.