"Did you make dinner?"

Translation: Zrobiłyście obiad?

[RickardRicky]

I answered "Czy przygotowałes obiad?".

[Paranoix]

It is correct but for me it sounds weird. We use "zrobić" more often. And remember you can skip "czy".

[JerryMcCarthy99]

Hmmm. Multiple choice requires both "Zrobiłaś obiad?" and "Zrobiłeś kolację?" ?. Yet, elsewhere, "obiad" seems to be "lunch", and "kolacja" seems to be "dinner".

[Makaronizm]

why not, "czy zjadłeś kolację?" ?

[Jellei]

Because the sentence mentions making, not eating. Your sentence is perfectly correct... it just doesn't mean what it was supposed to mean ;)