Retirement tax questions

So I should check "All of this distribution (from my TRS that is on my 1099-R) was an RMD"?

My broker said my TRS pension is not an RMD and that RMDs only come from IRAs (which I also have and am taking the correct amount of RMD from it.

Now I am really confused.  I do have a 1099-R for my TRS pension, but I don't understand how all of the money I get from TRS is considered RMD.

Need more information so I put the right thing on my taxes.