During a war which type of trade barrier is often used the most between the warring countries. a) embargo b) quota c) subsidy d) tariff

A) embargo is the correct answer. Embargo refers to the ban on trade with a particular country as a punishment for policies or acts of the embargoed country. The target country would not be able to make any form imports to other country who give the embargo (a trade war can occur).

Trade barriers are government-induced restrictions on international trade (the imposition of some sort of cost on trade that raises the price/availability of the traded products). The barriers can take the forms of "Tariffs" and "Non-tariff barriers to trade" (embargo).

to extend a country’s power and influence

social contract theory, nearly as old as philosophy itself, is the view that persons' moral and/or political obligations are dependent upon a contract or agreement among them to form the society in which they live