Concept:Economic integration removes trade barriers between member countries, thereby expanding the available market for goods and services.
Explanation:A free trade area, customs union, common market, and economic union all increase market size.
Common agricultural policy and common currency exist only in deeper forms of integration.
Free movement of factors of production occurs only in a common market or economic union, not in all forms.
Therefore, the benefit common to every level of economic integration is the enlargement of the market.
Answer:B. the size of the market is widened