@guy038 ,
Although I frequently use the ALT+MouseSelect column editing, I had never looked in the Column Editor dialog box, and didn’t know it had the auto-number feature. I’ll have to keep that in mind. I love learning new-to-me features in NPP.
And your regex mastery always astounds me. :-)
I would make one change to allow @CTL-Signup’s original asterisks (which I assume were marking either the “right” answer or the “selected” answer) to be preserved, which in my tests seems to work by modifying the first
SEARCH (?-s)^\R|\R(\*?\l\))|(.+)
Explanation: the same as Guy’s, except allow zero or one asterisk before the lowercase letter: \* indicates a literal asterisk; ? indicates “match 0 or 1”.