In Belgium, the French-speaking community was wealthier and had more access to education and economic development compared to the Dutch-speaking community, who were marginalized for a long time. The Dutch-speaking community only started gaining access to economic benefits and education later on, especially after reforms that promoted equality. This made Reason (R) a valid explanation for Assertion (A).
Conclusion.
Both Assertion (A) and Reason (R) are correct, and Reason (R) correctly explains Assertion (A), making option (A) the correct answer.