It was then put on the market and was on the market for over a year (approx 18 months) before it finally sold.
The key thing here is that you "did not rent or attempt to rent" out the property after the last renter moved out. Therefore the property would be converted to personal use the day after the last renter moved out. This stops depreciation on all rental assets. Additionally, rental expenses incurred after that date are no longer deductible as rental expenses. But they "may" be property improvements or could possibly qualify as sales expenses - even if incurred in the tax year before you actually sold the property. It just depends on what the precise expense was for.
Based on your dates, you did not sell the property in the same tax year the last renter moved out. Therefore you would report the sale in the "sale of business property" section.
If you qualify for the "lived in two of last 5 years" capital gains exclusion, the "sale of business property" section will handle this just fine.
