STRs - Schedule E, Vacation home or Commercial

[AJ D.]

I am trying to understand what a STR would be considered in terms of the IRS on Schedule E.
In my particular situation this is a true STR (average stay less than 7 days) I self manage the property and materially participate, and I do not stay at the property for personal use. 

For Schedule E - would this mean I select "#3 Vacation/short term rental" or "#4 Commercial" for the Property Type?

[Michael Plaks]

Quote from @AJ D.:

My understanding is a short term rental life span is considered 39 years (rather than 27.5), so does that mean I can consider it a "Vacation/short-term rental" in terms of property type, but still depreciate it over 39 years? 
Or would classifying it as #3, mean it too has to be depreciated over 27.5 years?

#3, 39 years