And the third situation is the men in both stories are the same person.
(These scenarios did happen, or at least I claim they did.)
Your students would have a problem coming up with a plausible scenario for any of these, but assuming it could be done, then an important conclusion follows. The conclusion is that these scenarios are possible. That doesn’t mean true, it just means that given what we know, we can’t rule them out.
The reason this is important is because we often reject stories in which too many pieces are missing. I think this is why, for example, an entire Jewish village (Sighet) in the path of the Nazis rejected a warning by an eye-witness of the awful fate that was in store for them. I suppose wishful thinking might have played a part, but my guess is that they simply couldn’t come up with a scenario in which people from an advanced country such as Germany would want to kill harmless villagers who mind their own business. And rationally, they should have been correct, but there many missing pieces to the puzzle which they knew nothing about.
Admittedly, there are real scenarios where no student of yours could up with a plausible scenario. For instance, if you told your students in the first days of the internet that there would be a social site called Facebook, they could accept that. If you said that people would reveal details about themselves, such as birthday, gender, family photos, etc, your students would yawn. But then you say that you wanted your students to explain that Facebook would have the following choices for gender:
The reason that the children have no fathers is that government pushed them out. I saw it with friends in the sixties. All they talked about was getting pregnant so they could get on welfare and get their own apartment away from their parents. Many never finished school. If they [the government?] found the men living with them they cut off the money. The men could live on very little so they had no reason to advance or become successful. They lived in what we called flophouses and could sit and get high and have a good time. Soon that good time took its toll on the body and that part time job wouldn’t buy the drugs they needed to get high. so they stole and sold it to the dealers who sold it to the black market shops. I had so many friends who went this route.
Clinton and Obama (a pamphlet) by David Horowitz
http://townhall.com/columnists/walterewilliams/2016/07/20/challenges-for-black-people-part-ii-n2194173 (one of the comments)
Elie Wiesel’s book “All Rivers Run To The Sea”