Which of the following is not true about the MACRS depreciation system:

a. A salvage value must be determined before depreciation percentages are applied to depreciable real estate.
b. Residential rental buildings are depreciated over 27.5 years straight-line.
c. Commercial real estate buildings are depreciated over 39 years straight-line.
d. No matter when during the month depreciable real estate is purchased, it is considered to have been placed in service at mid-month for MACRS depreciation purposes.