Hello, could anyone please help me with this macroeconomic multiple-choice question?

Increasingly, over the past two millennia, international trade has come to be characterized less by countries (or their representatives) trading with each other, and more by their private agents (e.g., individuals, corporations) trading with each other. What has this meant for theoretical conceptions of international trade? It has meant that theoretical conceptions of trade have become more complex o with the move from partial to general equilibrium. It has meant that theoretical conceptions of trade have become less complex with the move from general to partial equilibrium analysis. More abstraction from reality, as economic theoreticians make assumptions, o such as a representative firm that exists solely to maximize profits, and that all are identical. Less abstraction from reality, as economic theoreticians drill down to the level of the firm, which allows for a higher degree of realism based on data and observation. A different type of abstraction, going from 2-dimensional models of country o trade to 2-dimenionsal models of industry and firm behaviour and performance.