After completing the Form 1099-R there is a following screen which asks directly Was (Name) Employed as a Public Safety Officer?

See screeshot

If you bypassed this screen then return to the Form 1099-R section to edit your 1099-R.  Continue with the section until you are on the screen to answer the PSO question.  Then continue with the section until it completes.

Enter 1099-r in the Search box located in the upper right of the program screen.  Click on Jump to 1099-R