In economics, currency is defined as

• A. A collection of coins and notes used in trade nationally
• B. The value of goods and services at a given time
• C. Money; any other medium of exchange
• D. A unit of account used by a government

Answer: (C)

Currency is money that functions as the medium of exchange in daily transactions. In modern economies this isn’t limited to physical coins and banknotes; it includes other widely accepted forms that people use to pay and settle debts, such as electronic money or bank deposits. That broad idea—money as the accepted means of payment—is what this option captures best: currency is money, and it encompasses other forms that serve as the medium of exchange. The other choices miss this scope: one sticks to physical cash, another talks about value or price rather than payment methods, and the last describes a function (unit of account) rather than the medium of exchange itself.