The answer to this question can be found in the Prologue to Collapse. It is found in the pages after the first mention of the framework. I have this book on Kindle only and so I can’t give you a page number, but you can look up “neighbors, hostile” in the index to find this area of the book.
In the Prologue, Diamond offers five factors that can determine whether a society collapses. Different societies can be impacted by different combinations of these factors. The factors are
- Environmental damage
- Climate change
- Hostile neighbors
- Trade with friendly neighbors
- Society’s response to problems
Of these, your question asks about all but environmental damage. Let us look at what each of these means, with reference to the examples cited in your question.
One factor that can help to make a society collapse is pressure from hostile neighbors. Diamond mentions the fall of the Roman Empire as a classic example of the importance of this factor. Therefore, Option C goes with “hostile neighbors.” Diamond points out that the Roman Empire is said to have fallen in large part because its “barbarian” neighbors kept invading it.
A second factor is climate change. Diamond points out that this does not have to mean human-made climate change. This is where the eruption of Mt. Tambora in 1815 comes in. Diamond says that this eruption caused the climate to cool so much that famine broke out even in such places as Europe and North America. Therefore, Option D goes with “The impact of climate change.”
A third factor is trade with friendly neighbors. What Diamond is saying here is that your society can collapse if your friendly neighbors stop trading with you. In good times, friendly neighbors trade with one another. Diamond says, for example, that other countries sell wood to Japan today. This helps Japan’s society survive. If the neighbors were to stop trading with Japan, Japan would be hurt. Therefore, Option A goes with “friendly neighbors.”
Finally, there is society’s response to a problem. Different societies can all face the same problem, but respond in different ways. Diamond says that the people of the New Guinea highlands responded well to deforestation and therefore their society did not collapse. Therefore, Option B is the correct answer to “Society’s response to a problem.”