The fundamental law containing the rules and principles governing a country is the

Step 1: Analyze the question The question asks for the fundamental law that contains the rules and principles governing a country. The key phrases are "fundamental law" and "rules and principles governing a country."

Step 2: Explain the concept A constitution is the supreme or fundamental law of a state. It sets out:

• How government is organized (the executive, legislature and judiciary)
• The powers and limits of each organ of government
• The rights and duties of citizens
• The principles by which the country is run

In Nigeria, this is the 1999 Constitution of the Federal Republic of Nigeria (as amended). Every other law must agree with it. Any law that contradicts it is void to the extent of that inconsistency.

Step 3: Check each option

• A. Convention: These are unwritten customs and practices that are followed over time (common in Britain). They are not the fundamental law itself.
• B. Constitution: This is the supreme law that contains the basic rules and principles of governance. ✔
• C. Acts of parliament: These are ordinary laws made by the legislature. They are subordinate to the constitution.
• D. Judicial review: This is the power of courts to examine whether laws or government actions are constitutional. It is a process, not a body of law.

Step 4: Answer The correct answer is B. constitution.

Exam tip: When you see "fundamental law," "supreme law," or "grundnorm," think constitution. Remember the order of authority: Constitution > Acts/Statutes > Subsidiary legislation (bye-laws).