Mort is the owner of an apartment building containing ten identical apartments. Mort resides in one apartment and rents out the remaining units. For 2016, the following information is available: Gross rents $21,600 Utilities for total building 2,500 Maintenance and repairs (rental apartments only) 1,050 Advertising for vacant apartments 300 Depreciation of building (all ten units) 4,000 What amount should Mort report as net rental income for 2016?