Personnaly I would had choosed too broad.

I can't talk for the users that did the VtC, but after thinking to it, that reason could mean your simulator might be bugged and it would fall as a tip to use another test methodology with another simulator, and ´I want to understand how X work' trigger the learning recommandation from the same close reason too.

In the end its surelly a better suited close reason than too broad that I would had choosen at first.

nb, a comment from us would had not hurt, but be easy with us, the review queue is hard to clear these days.