The collapse of the Soviet Union was primarily influenced by multiple factors, but the most relevant answer from your options would be B. the falling price of oil.
In the 1980s, the Soviet economy was heavily reliant on oil exports, and when global oil prices fell, it significantly weakened the Soviet economy. Additionally, other factors such as political reforms, economic inefficiencies, and nationalist movements within various Soviet republics contributed to the collapse.
While overproduction of agricultural products and other issues played a role, the falling price of oil had a significant immediate financial impact. Vladimir Putin's rise to power occurred later, after the dissolution of the Soviet Union in 1991.