Answer:
C. Representative economy
Step-by-step explanation:
Representative money refers to something without any intrinsic value that can be used as a medium of exchange.
Even though that medium does not necessarily have intrinsic value, it can be considered something that desired when the majority of people in that society accepted it as a medium of exchange.
In the example above,
The certificate is just a piece of paper. Outside of the war period, that paper will have no value in that society.
But, during wartime people realized that they need to do something drastic to survive, so the majority of the people in that small country acknowledge that piece of paper as something valuable.