Form 1099-B Sales Info answer for Incentive Units

My husband received a 1099-B for the sale of Incentive Units (I think they are similar to RSUs).  In the beginning of the sales info section of the 1099-B, it asks "what type of investment did you sell?" and has stock (non-employee), cryptocurrency, mutual fund/index fund/ETF, bond, or options as possible answers.  Would the sale of Incentive Units be classified as an option?  I think that's the correct answer since employee "stock" is not an answer.

 

Thank you!