The most accurate response regarding the importance of the Democratic Republic of Congo to the Allies is:
It provided uranium that would be vital in building the atomic bomb.
During World War II, the exploitation of natural resources was critical for military and technological advancements. The Congo's rich mineral resources, particularly uranium, played a significant role in the development of nuclear weapons, which were crucial to the Allies' strategic military capabilities. While the other options touch on various aspects of the region, the supply of uranium is the most pertinent to the Allies' efforts during the war.