Finall Answer:
The sentence from the article that suggests a rise in population might have contributed to the crises is (C) "Some scholars believe that Europe had too many people."
Step-by-step explanation:
The sentence (C) implies that there's a perspective among scholars attributing Europe's crises to an excessive population. This idea indicates that an increased population might have strained resources, leading to issues like disease, famine, and labor shortages mentioned in other parts of the text.
This contention aligns with historical patterns where burgeoning populations often exacerbated societal problems, offering a key insight into the potential role of population growth in the crises discussed in the article.