When economies expand through industrialization, factories need a large supply of workers who can perform routine, low-skilled tasks. Immigrants often arrive with limited capital and varyingly limited English, so entry into these jobs is more accessible than specialized trades or professional roles. Unskilled labor in factories offers quick entry and the ability to pay living costs while learning on the job, which is why many immigrants found work in that segment. In contrast, skilled trades require training and credentials, farming typically involves rural opportunities, and banking demands established networks and education, making them less common entry points for new arrivals.

The main idea is that the Bonus Army was pushing for immediate cash bonuses for World War I veterans. The government had authorized a bonus to be paid in 1945, but the veterans argued they needed relief right away due to the Depression. Their goal was to get the promised money accelerated and paid out now, not to change Social Security policy or subsidies. That’s why the option about supporting the early payment of money promised to veterans best fits what the group sought.

The key idea is that muckrakers and urban photographers aimed to reveal the harsh realities of urban life to spur reform. They used investigative writing and powerful images to show conditions like overcrowded tenements, poor sanitation, and brutal working environments. By bringing these problems to the attention of the public, they hoped to mobilize people and push lawmakers to act, leading to reforms in housing, public health, and labor laws. That matches the answer because it centers on exposing the plight of the unfortunate to spark change. Historical examples include Jacob Riis’s photographs of New York tenements and other reporters whose work helped drive Progressive Era reforms. The aim wasn’t profit, strikes, or war advocacy, but raising awareness to provoke policy and social improvements.

The main idea here is how U.S. Senators are chosen. The quote points to voters directly selecting their Senators rather than having them chosen by state legislatures. That describes the change made by the amendment, which established that Senators are elected by the voters in each state, shifting power from state legislatures to the people. This reform was ratified in 1913 to curb deadlocks and reduce corruption or undue influence in how Senators were placed in office, aiming for greater accountability to the electorate. The other amendments focus on who can vote or when, not on how Senators are selected. The 15th prohibits racial discrimination in voting, the 19th extends suffrage to women, and the 26th lowers the voting age to 18. None of these address the method by which Senators are chosen, so the described idea fits best with the amendment that moved to direct popular election of Senators.