Answer: The correct answer for the fill in the blank is - medium of exchange.
Explanation-
When we use paper money to pay for food, the money is a medium of exchange as we are exchanging our money with their food. So, it plays a role of medium of exchange in purchasing our food.
On the other hand, unit of account is also a feature of money but it only indicates the price of food at which we are purchasing it. Store of value is used when we store our money as a wealth, then it becomes store of value .
Hence, medium of exchange is the correct answer.
