The best option that analyzes how language can be a divisive force in states where most people speak the same language is:
Despite speaking the same language, regional dialects can reinforce cultural differences and influence migration.
This response highlights how, even when a common language is present, variations in dialect can underscore and perpetuate cultural divides, leading to social tension and migration patterns, which are significant factors in understanding the divisive potential of language within a seemingly homogeneous linguistic context.