I think they're when you use a new term in the conclusion. Sometimes, the new term looks similar to the terms used in premises, but they are different.
As we're looking at a new term, we have no basis to draw a conclusion. Here's the example from the question (Answer E):
People living in open and democratic countries have customs that are determined at least in part by an inherited past. But no country's past is A PRODUCT OF FREE CHOICE. Thus people living in open and democratic countries can never be ENTIRELY FREE.
From the premises, we only know that customs in a country weren't from a free PAST. The conclusion, however, discusses the past, present, and future: NEVER BE ENTIRELY FREE.
As that's the first time the present and future are mentioned, we can't really evaluate it.
Another problem with this answer is that it would be possible for a country to be free now, even though it was not free in the past.
It's kind of like how in some movies, crime bosses get wealthy by commiting crimes, but they want their kids to be legit, so they use money from crime to start legal businesses. After a period of time, people forget where the original money came from and just believe that it's legit. The past does not equal the future.
