RMD

NOTE: 401(k) RMDs must be taken from each employer plan that you have.

if you have only one employer plan but multiple accounts you can take full RMD from any of them. I don't have a 401(K) plan but I have multiple IRA accounts (none inherited or subject to special rules). When I know I took the RMDs for the year, I leave those questions blank. They are only used by Tutbotax to compute the penalty for failure to take the RMD. Another option, again only available if you had only one employer plan 

1) check that the entire gross is the RMD

2) for the RMD amount use the gross from box 1 of the 1099-R

see this thread about correcting the issue if you had multiple 401(k) plans

https://thelink.ascensus.com/articles/2019/1/14/failing-to-remove-an-rmd-from-a-401k-plan-can-be-corrected