What is one example of a closed economy

The closed economy is a self sufficient economy. The countries following a closed economy system does not involve in the import and export of goods from other nations.  In these countries, all the goods are produced in the country is consumed within the country itself.

Brazil is a country, which can be said as closed economy as Brazil imports a very item from other nations. A Complete close economy system is not present in any country yet.

the answer would be d : p