Kate is an accrual basis, calendar-year taxpayer. On November 1, 2015, Kate leased out a building for $4,500 a month. On that day Kate received 7 months rental income on the building, a total of $31,500 ($4,500 7 months). How much income must Kate include on her 2015 tax return as a result of this transaction?

1. 4,500 2. 54,000 3. 9,000 4. 31,500 or 5. none