I know. And that is why I consider this exercise to be vague and imprecise.
On another page, I tried to detail the difference, because I run into it all the time.
My wife is gluten intolerant - and a whole lot more educated on the topic than I am. Therefore, almost always when I ask, "Can you eat this," I never mean "Kann man etwas essen."
Hence, my example: "Du kannst nicht das essen, aber er kann!"
If the sentence continues that way, "du" is of course the only option (btw., the word order should be "Du kannst das nicht essen, aber er kann."
But if the sentence stand alone, "Man kann das nicht essen" is one of the possible translations. And without context Duo has to accept both.