Correct Option: D. Issue of currency Detailed Explanation: To understand why option D is the correct answer, we need to look at the primary functions of commercial banks and the role of currency issuance in the banking system.

1. Functions of Commercial Banks:
2. Acceptance of Deposits (Option A): Commercial banks are financial institutions that accept deposits from individuals and businesses. This is one of their core functions, as it provides a safe place for people to store their money while also allowing banks to use these deposits for lending and investment purposes.
3. Lending of Money (Option B): Another fundamental function of commercial banks is to lend money to individuals and businesses. They provide various types of loans, such as personal loans, mortgages, and business loans, which help stimulate economic activity by enabling consumers and businesses to spend and invest.
4. Investment in Securities and Business (Option C): Commercial banks also invest in various securities, such as government bonds and corporate stocks. This function allows banks to earn returns on their excess funds and manage their liquidity. Additionally, banks may invest in businesses, either directly or through financing, which can help foster economic growth.
5. Role of Currency Issuance:
6. Issue of Currency (Option D): The issuance of currency is not a function of commercial banks. In most countries, including Nigeria, the central bank (in Nigeria, this is the Central Bank of Nigeria, CBN) is responsible for issuing currency. The central bank controls the money supply and ensures the stability of the currency. Commercial banks operate within the framework set by the central bank and do not have the authority to issue legal tender.

Why Other Options Are Incorrect:

• Option A (Acceptance of Deposits): This is a primary function of commercial banks. They provide a safe place for customers to deposit their money, which is essential for the banking system's operation.
• Option B (Lending of Money): Lending is a critical function of commercial banks. They use the deposits they accept to provide loans, which is how they generate income through interest.
• Option C (Investment in Securities and Business): This is also a valid function of commercial banks. They invest in securities to manage their assets and liabilities effectively and to earn returns on their capital.

Common Pitfalls:

• Students may confuse the roles of commercial banks and central banks, particularly regarding currency issuance. It's essential to remember that while commercial banks play a vital role in the economy, they do not issue currency.
• Another common mistake is overlooking the importance of each function of commercial banks and assuming that all banking activities are interchangeable.

Revision Summary:

• Commercial banks accept deposits, lend money, and invest in securities and businesses.
• The issuance of currency is the responsibility of the central bank, not commercial banks.
• Understanding the distinct roles of commercial and central banks is crucial for grasping the banking system's structure.
• Always differentiate between the functions of various types of banks to avoid confusion in exam scenarios.