In essence you have sold it. So answer "yes" to the sold via sale question. We have had discussions on the options here and I believe it is cleaner if you answer it this way.
As a partner in the partnership you should have been maintaining a basis schedule. This begins with your original capital contribution and is updated annually for the applicable lines on your K-1.
You need to either create this basis schedule or update it for your final K-1 EXCLUDING any liquidating distribution.
Once you have your basis schedule up to date, you now have what TT is asking for; You should know when you acquired the partnership interest, just use 12/31/2016 if no other sale date was provided, your cost is equal to your updated basis figure and the sales price is your liquidating distribution.
This final gain or loss will then be reflected on Schedule D and the applicable form 8949.
*A reminder that posts in a forum such as this do not constitute tax advice.
Also keep in mind the date of replies, as tax law changes.
