Final answer:
The Soviet Union's main concern during the 1948 Berlin crisis was the formation of a capitalist Western German nation. They responded by initiating the Berlin Blockade, hoping to stop the Western Allies' plan by cutting off supply routes to West Berlin, which spurred the Allies to conduct the Berlin Airlift.
Step-by-step explanation:
The Soviet concerns when the Berlin crisis began in 1948 concentrated on the prospect of their former wartime Allies, specifically the United States, Britain, and France, creating a unified Western German nation that would operate under a capitalist system.
The Soviets saw this as a threat, hoping instead to keep Germany disunited and weak. Accordingly, the correct answer to the student's question is D. A Western German nation would be formed under capitalism.
When the Western powers moved to merge their zones to form the Federal Republic of Germany (FRG or West Germany), and when they introduced a new currency (the Deutsche Mark) to facilitate Marshall Plan aid, the Soviets reacted by instigating the Berlin Blockade.
This act aimed to force the Allies to abandon their control of West Berlin by cutting off all essential supplies, hoping it would lead to the Allies relinquishing their plans for a Western capitalist Germany.
The Soviets went further and formed their own state in response, establishing the German Democratic Republic (GDR or East Germany). The situation in Berlin became emblematic of the broader geopolitical struggle between the capitalist West and the communist East during the early stages of the Cold War.