Final answer:
The ban on importing agricultural products from the European Union by the Russian Federation in 2014 constitutes a nontariff barrier, which is a form of protectionism employed to make importing goods more difficult and costly.
Step-by-step explanation:
In 2014, when the Russian Federation banned the import of many agricultural products from the European Union, it was engaging in what is known as a nontariff barrier. This type of trade restriction leverages rules, regulations, inspections, and paperwork to make it more difficult and costly to import products, falling under the umbrella of protectionism.
Nations might impose these barriers for various reasons, including to protect industries that are of national importance, whether for security reasons or because the industry is a core part of the nation's cultural identity. For example, geographically adjacent rivals or nations with conflicting political agendas might find it counterintuitive to trade certain goods that are critical to national security or identity, despite possible economic advantages.
Therefore, the ban by the Russian Federation would be considered as a response encapsulated in choice A: Nontariff Barriers.