Public corporations were established by an act of

Analyze the question: The question asks which legal instrument is used to establish public corporations. The phrase "an act of" is a strong clue, because an "Act" is a law passed by the legislature.

Explain the concept: Public corporations (also called parastatals) are business or service organizations owned and financed by the government. They are set up to provide essential services or run strategic industries. Examples in Nigeria include NNPC, NEPA (now PHCN/TCN), the Nigerian Ports Authority, and the Central Bank of Nigeria.

Each public corporation is created by a specific law (an Act, or a Decree during military rule) that spells out:

• its objectives and functions
• its powers
• its structure and management
• its sources of funds

In a democracy, the body that makes such laws is the legislature, called Parliament in the general Government syllabus and the National Assembly in Nigeria.

Step-by-step solution:

1. "Act" means a law passed by the legislature, so the answer must be the lawmaking body.
2. B. Memoranda of understanding are agreements between parties and are not laws that create institutions.
3. C. Constitution is the supreme law. It may mention certain bodies, but public corporations are not created by the constitution itself.
4. D. Executive order is a directive from the executive and is not an "act".
5. A. Parliament passes Acts, so it is the correct choice.

Answer: A. parliament

Exam tip: Remember "Act = Assembly". Whenever you see "established by an act of...", think of the legislature. Under military rule, the equivalent was a "Decree".