In here, this is the final prompt before Yui creates the RAS Message. You should type Yes or No, depending if you want Yui to enlist only one role at a time or enlist in any roles at any given time. If you're having trouble choosing, let the descriptions help you below:
You want people to only have one role at a time, like for roles that answer the questions:
Are you Male or Female?
How tall are you?
What is your age?
You can only answer these questions with a Definitive Answer. You can't be 4'10" and 5'11". So you have to be only one choice.
You want people to react multiple times for all the roles they apply to, this could be used to answer the questions like:
Do you like Anime or Manga?
Do you like Vanilla or Chocolate?
Which Waifus are your favorites?
These questions can be answered with an Infinitively-Many Answers. I can read the Manga and Watch Anime, thus would be no difference if I applied to both. So you could have both or all the choices if you chose to.