Please explain

Robert Reed, a bachelor, maintains his parents in a nursing home. They have no income of their own and are completely dependent on their son. His parents are 75 and 72 years of age. Robert has the following sources of income: 4- Salary $45,000 750 800 500 Interest on Municipal Bonds Interest on Bank Accounts Dividends on Common Stock of U.S. Corporation Robert has itemized deductions of $12,000. Robert owns several apartment buildings. His net rental income was $3,000 for the year. Then, on December 31 one of his best tenants brought in a check for $500. This money covers the months of December and January. Robert is confused on how to account for this rental income. It is not included in the $3,000 listed above. Compute Robert's taxable income