Where is the blank? I’m sorry to answer without a answer just elaborate in comments
Triangular trade or triangle trade is a historical term indicating trade among three ports or regions. Triangular trade usually evolves when a region has export commodities that are not required in the region from which its major imports come. Triangular trade thus provides a method for rectifying trade imbalances between the above regions.
The Electoral College is "none of the above", since in fact it is a system in the United States in which electors in every state and Washington DC elect the President.
