What is the primary principle behind the EU's common market established in 1993?

The primary principle behind the EU's common market, established in 1993, is the free movement of goods, services, capital, and labor. This principle aims to create a single market where barriers to trade and movement between member countries are removed, facilitating economic integration. By allowing these four freedoms, the EU enhances competition, encourages innovation, and promotes an efficient allocation of resources across member states.

The inclusion of all four elements—goods, services, capital, and labor—ensures that businesses can operate seamlessly across borders, consumers have access to a wider variety of products and services, and individuals have the opportunity to work and live in different member countries without restrictions. This comprehensive approach is fundamental to the EU's economic strategy and is essential for fostering growth and cohesion among member states.

The other options, while related to aspects of the market, do not encompass the full scope of the common market's principles. Focusing solely on any one of the freedoms would not capture the integral nature of the common market, which relies on the interconnectivity of all four aspects.