Nonresidential real property in the U.S. (such as office buildings, factories, and workshops) placed in service on or after May 13, 1993, is depreciated using The straight-line method over 31.5 years. The straight-line method over 39 years. O A 150% declining basis method over 31.5 years. O A 150% declining basis method over 39 years. Mark for follow up