Which of the following terms describes informal agreements between countries regarding trade?

The term that describes informal agreements between countries regarding trade is "free trade." Free trade refers to a situation where countries allow goods and services to be exchanged across borders without restrictive barriers such as tariffs or quotas. The essence of free trade is built on the mutual understanding and informal agreements that promote open markets and encourage economic cooperation between nations. This concept facilitates easier access to goods and a more efficient allocation of resources, enabling countries to specialize in their strengths.

Understanding the context is crucial; both quotas and trade regulations impose restrictions on trade rather than encouraging it. Quotas set limits on the quantity of goods that can be traded, while trade regulations encompass formal laws and standards that govern trade practices, which can include tariffs or exclusionary practices. Barriers to entry involve obstacles that prevent new competitors from easily entering a market, which again does not align with the concept of free trade. Thus, the focus on informal agreements fostering economic collaboration makes "free trade" the most fitting term in this context.