They couldn’t agree on how to handle discrimination Du Bois wanted to be violent and Washington was peaceful.
Parliament of the United Kingdom
They spread like wildfire. For a new factory to beat the competition, it had to be built quickly. Laborers needed fast, cheap housing located close to work. Roads would be hastily built to connect the factory with the market. There was no grand design, and consequently, the new American city spread unpredictably. Urban sprawl had begun. But the growing beast brought benefits that raised the standard of living to new heights. The modern American city was truly born in the Gilded Age. The bright lights, tall buildings, material goods, and fast pace of urban life emerged as America moved into the 20th century. However, the marvelous horizon of urban opportunity was not accessible to all. Beneath the glamour and glitz lay social problems previously unseen in the United States.
Many leaders tried/pushed for a steady build up for their own countries armed forces to show the power they had and tried to maintain a balance of power.
I'm pretty sure the answer is C. Native American relocation, but I could be wrong.