The correct answer is A.
Creating a common market was one of the original core objectives of the European Economic Community, founded in 1957. A common market is a free trade area, a trade bloc that shares common economic policies and freedom of mobility of capital, goods, services, and labor with the goal of finally removing all trade barriers. It was achieved by the European Community by 1999 with the creation of a common unique currency, the Euro, thus creating the European Union as an economic and monetary union.