Goodwell will recognize 3 months (Oct 1 - Dec 31) of rent revenue earned, and will reduce (debit) the unearned rent revenue for those 3 months.
2,500 x 3 months = 7,500
Journal Entry, Dec 31:
Unearned Rent Revenue: 7,500
Rent Revenue: 7,500
The new Unearned Rent Revenue Account balance will be:
12,500 - 7,500 = 5,000