"I drink water to every meal" doesn't sound right. I put, "I drink water at every meal", which is correct but got marked wrong. "I drink water with every meal" should also be acceptable, if it isn't already.
"I drink water to every meal" is definitely not valid English. If it's still in the valid answers list it should be taken out (native speaker UK/IRL).
It's now accepting "I drink water with every meal", which is the most natural way to express this idea in English.
Seems like they took that answer out. I made that mistake multiple times, since to is simply so natural to use in this context in my language :p
Just like genitive = accusative or singular genitive=plural nominative that things happen.
Do mojego posiłku. (Genitive) Po moim posiłku. (Locative)