Answer:
D. must follow decisions made by the central government.
Step-by-step explanation:
A unitary system of government has a unique center of politic power that takes action throughout the state's territory, employing its agents and local authorities delegated by the central power.
It has only one legislative power who runs all over the country, judicial power and a Supreme Court, which jurisdiction is all the country, and also it has one executive power and a constitution that rules throughout the country.
Its precedent is the absolutist states, the territorial, legal and legislative modules are all unified. It hasn't got interior administration, possessing a power centralization in hands of the central power. Its sovereignty is unique.
As I said in this system it has just only one constitution which rules all over the country and which is respected and followed thanks to the central government whose responsibility is controlling all state matters and making decisions and taking actions.