Which statement describes a major advantage of a federal system of government over a unitary system

The capital does not always know what is right for states while the states themselves know their issues more acordingly

The correct answer is A. fuiste.
The verb ser (to be) in Spanish is an irregular verb, which means that you need to learn its various forms by heart. In the example above, we need the preterite form of the verb ser, and it goes like this:
1. yo fui                    1. nosotros fuimos
2. tu fuiste                2. vosotros fuisteis
3. el fue                    3. ellos fueron