(This is supposed to be a reply to Terry53029's answer.  It looks like the replies aren't showing up under the right post currently.)

You're thinking of something different.  The depreciation period is determined by § 168, which results in the correct answer which is it's 39 years if the average stay is 30 days or less.

What you're thinking of is § 169 (the passive loss rules), which is unrelated to determining the depreciation period.  Under § 169, a rental is potentially non-passive if it has an average stay of 7 days or less (or less than 30 days with "significant personal services"), and also they materially participate, then it is non-passive.  But it still goes on Schedule E, not C.  The difference is it can bypass form 8582.  To do that, choose the non-passive option in your tax software.