This sentence would not be possible sentence in the dialects of American English with which I am familiar. Without a unit, either "loaf" or "slice," bread is dealt with as something that is not countable. Thus, one might say "a whole slice of bread" or "a whole loaf of bread" (or a whole roll, muffin, biscuit, etc.), but one would no more say "a whole bread" than "a whole sugar" or "a whole milk," which, of course, mean other things.
It seems to be something peculiar to the way we talk about bread, too, since I can ask "Have you eaten the whole cake?" or "Have you eaten the whole pie?" It is only with bread that I have to ask "Have you eaten all the bread?" in the same way I would ask whether you had drunk all the milk.
I did not see anything that would be Danish for loaf so I left it out, even though as the other commenter pointed out, the phrase would never be used that way in english. But if it IS used that way in Danish, we should know. IF it can be loaf or slice, either implied, in my opinion there are too many variables here to make it a meaningful test question.