Which of the following maps would be best suited for showing the volume of trade between countries?

A flow map is the most appropriate choice for illustrating the volume of trade between countries because it visually represents the movement or flow of goods and services across borders. Flow maps utilize arrows of varying thickness to indicate the volume of trade, with thicker arrows representing larger volumes and thinner arrows indicating lesser amounts. This visual representation allows for an immediate understanding of trade relationships and patterns between different regions or countries.

In contrast, a political map primarily displays boundaries, names, and locations of political entities, without conveying any specific information about trade volume. A choropleth map uses different shades or colors to represent statistical data for various regions, such as population density or economic indicators, but it does not capture the dynamics of trade flow. A topographic map focuses on terrain and elevation rather than trade statistics. Therefore, the flow map is uniquely suited to convey the specific information regarding trade volumes, making it the best option for this purpose.