What code is in box 7 of the 1099-R you received?
Actually the RMD question is only material if only the RMD amount was distributed. If the entire IRA was liquidated and distributed then the answer is irreverent - just say that it was all a RMD.
TurboTax only asks this question to determine how much might be eligible for rollover. However, since a non-spouse beneficiary is not permitted to roll any of this distribution over, it doesn't matter how you answer the question. Simply say it was all RMD.