Concept:The Maginot Line was a system of fortifications built by France to protect its border with Germany after World War I.Explanation:France constructed the Maginot Line in the 1930s along its eastern frontier. Its main purpose was to prevent a German invasion. However, during World War II in 1940, German troops bypassed the line by attacking through Belgium. This made the fortifications ineffective. Therefore, the Maginot Line was built between France and Germany.Answer:Option A – France & Germany