Retirement tax questions

I had a similar problem for 2018. My question is about 2019.  I forgot my 2018 RMD and took it in 2019 before filing my tax return.  I'm squared away with that.  But in reporting the 2018 RMD in 2019, when entering the info on the 1099-R, TT asks: "Was this withdrawal an RMD for 2019?" The answer is no, but the two options are: "Yes, some or all of this withdrawal was an RMD, or No, none of this withdrawal was an RMD."  Which box do I check?