Correct answer: A. Rights and taxes differed by birth-based groups
Explanation: The direct answer is A: rights and taxes differed according to birth-based groups. French society was legally divided into estates, and this was not merely a difference in income or occupation. The First Estate, Second Estate and Third Estate had different privileges, duties and social positions. Clergy and nobles enjoyed important advantages, while the Third Estate, despite containing most of the population, carried many taxes and obligations. Therefore the law treated people differently because of the estate into which they were born. B is wrong because people did not all have one equal vote in the old order. C is wrong because taxes were not charged equally; the burden was unequal. D is wrong because peasants generally lacked special privileges and faced dues and taxes. The key fact chain is legal division by birth, unequal rights, unequal taxation and social inequality.