25. Billy Dent, as the owner of an apartment building, receives and makes the following payments during 2020: $5,000 4,000 Received in January 2020 rent that was due in December 2019 Received in December 2020 rent not due until January 2021 Security deposit which is to be refunded when tenant vacates the apartment 500 How much rental income must Billy Dent include on his 2020 income tax return