Question: Which of the following situations does NOT occur in a federal state?
A: Central government possesses a two-level system of government.
B: Central government governs country as a single unit.
C: It often possesses a written constitution.
D: Lower-level divisions have unique powers.
Please eliminate two incorrect options first, then think it step by step and choose the most proper one option. Provide two versions of response separated with exactly 6 asterisk symbols: ******.
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