The ultimate source of power and authority which sets the state apart from other forms of political organisations is referred to as

Step 1: Analyze the question The question asks for the term describing the ultimate source of power and authority that makes a state different from other political organisations (such as political parties, pressure groups, or local associations).

Step 2: Explain the concept In Government, a state has four key elements: population, defined territory, government, and sovereignty. Sovereignty is the supreme, absolute, and final authority of a state to make and enforce laws within its territory, free from external control. Other organisations (e.g., a church, a trade union, or a political party) may have rules and members, but none has this supreme legal authority.

Step 3: Check each option

• A. Constitutionalism: the idea that government power should be limited by a constitution. It is about limiting power, not the ultimate source of authority.
• B. Checks and balances: a system where the arms of government (executive, legislature, judiciary) restrain one another to prevent abuse of power.
• C. Rule of law: the principle that everyone, including leaders, is subject to the law and equal before it.
• D. Sovereignty: the supreme power and authority of the state, which distinguishes it from all other associations. This matches the question.

Step 4: Answer The correct option is D. sovereignty.

Tip: Whenever you see "supreme," "ultimate," "final authority," or "what sets the state apart," think sovereignty. Remember the four elements of a state with the phrase P-T-G-S: Population, Territory, Government, Sovereignty.