It’s D because in the 1960 they sort of had a connection.
They didn't go far enough because although all types of institutionalized racism was forbidden by constitutional means, it didn't stop people from being racists. They still behaved like racists and often it would happen that people of color would get punished much more in court than Caucasian people, or people who were racists and did bad things against the African-American population would walk free, especially in smaller communities.
The use of women, children and immigrant allowed industrialists and factory owners to keep wages low for native born men. This was an important catalyst for the organization of labor unions, Children often worked long hours for low pay. The same was true of women and immigrants.
The real causes of World War I included politics, secret alliances, imperialism, and nationalistic pride. However, there was one single event, the assassination of Archduke Ferdinand of Austria, which started a chain of events leading to war.
