Europe 1940 for sure.
Most amount of pieces, best options, best map to make alternate scenario’s!
It’s hard to quiz on the rules, since there are some many official versions as well as optional rules.
For example, National Advantages made unit capabilities differ by countries (one of the quiz questions)
17/20 I miss understood what they were asking in the 3 I got wrong and guessed right on 3 others that was kind of hard to understand what they were asking. Again it’s hard to ask about rules when there’s been so many games and rules sets.