Centralization is a system where power and authority are concentrated in a central governing body or institution. It is characterized by the centralization of decision-making, control, and resources.

Let`s dissect each option to understand why option 4 is the correct answer:

Option 1: National unity - Centralization often promotes national unity by establishing a strong central government and ensuring uniform laws and policies across the country. Therefore, this is a feature of centralization.

Option 2: Uniformity - Centralization aims to achieve uniformity by standardizing processes, policies, and systems across different regions or departments. This ensures consistent implementation of laws and regulations. Hence, uniformity is a feature of centralization.

Option 3: Prosperity - Centralization does not guarantee prosperity. It can promote economic growth and development if properly implemented, but it can also lead to inequalities and hinder local decision-making and innovation. Hence, prosperity is not necessarily a feature of centralization.

Option 4: Liberty - Centralization often restricts individual or local liberties because decision-making power is concentrated in a central authority. Local autonomy and freedom to make decisions may be limited. Therefore, this is the correct answer as it is not a feature of centralization.

In conclusion, while options 1, 2