I would say B.
as Imperialism during the industrialization era allowed for nations to colonize under developed nations in Africa and Asia. Which gave them access to their natural resources and markets
For example the British Empire had a vast amount of land with a array of resources but they held economical markets in Asia (China, India and Malaysia)
I think it's C , hope this helps :)
Answer: B. Increased production of war materials
C. A reduction in the number of European Immigrants
Explanation:
Due to WWI, there was a severe shortage of labor since many former factory workers had enlisted in the army and not many European migrants were pouring into the country. With demand for war materials at an all time high, African Americans were compelled to migrate to the more indutrial north to become industrial workers, with higher wages than those of an agricultural worker in order to make up for the lost manpower.