Another four-year-old funny

We play a game at my house that my kiddos love. We call it "Fruit or Vegetable". I will name a fruit or veggie and, as quickly as they can, my kiddos will yell out what they think it is...fruit or vegetable. Mostly, they like the noises I make when they get the answer right (ding, ding, ding) or wrong (ehhhhnnn) It goes something like this:
Me: "Banana: fruit or vegetable?"
Kiddos: "FRUIT!"
Me: "Ding, ding, ding!"

After playing this game a few times my kiddos got pretty good at remembering what things were, so now I try to stump them and make things more challenging. The other day this game went like this:

Me: "Potatoes: fruit or vegetable?"
Kiddos: "VEGETABLE!"
Me: "Ding, ding, ding!" French fries: fruit or vegetable?"
Kiddos: "VEGETABLE!"
Me: "Ding, ding, ding!"

So, curious as to whether or not they knew why french fries might be a vegetable I asked, "Do you know where french fries come from?"
My daughter responded, "Yeah, McDonald's!"