The government that typically has unlimited power is B. socialist oligarchy. In a socialist oligarchy, power is concentrated in the hands of a small group, often leading to limited political freedoms and control over various aspects of life without the same checks and balances that might exist in other systems.
The other options, while they may have varying degrees of power concentration or governance styles, generally have mechanisms that limit governmental power, such as constitutional frameworks (in the case of constitutional monarchies and parliamentary systems) or more distributed power structures (in unitary systems).