Answer: b. only open economies
A closed economy is a self=sufficient economy and does not need trade activity with outside economies. There are no imports and exports.
An open economy is its opposite. It is the type of economy which interact with other economies.
Trade exists in many forms like managerial exchange, technology transfers, and all kinds of goods and services. Economic advantages for citizens of a country with an open economy: 1) Consumers have larger variety of goods and services from which to choose and 2) they have the opportunity to invest their savings outside the country.
