Translation:You have prepared the food
"You have fixed the food" and "you have prepared the food" have the same meaning in English. Both should be accepted
In American English anyway. When you guys say that, it sounds to me like "I have repaired the food", haha.
"You have prepared a meal" should also be accepted. The course has come a long way with English usage of definite/indefinite/no article, but still not quite there yet :) Reported.