Final answer:
The United States government's failure to honor its promises is exemplified by the Massacre at Wounded Knee in 1890, where U.S. troops fired indiscriminately at surrendering Lakota men, women, and children, killing up to 300 despite previous treaties guaranteeing their land and rights.
Step-by-step explanation:
The incident described as an example of the United States government going against its promises is d) Massacre at Wounded Knee. The Wounded Knee Massacre in 1890 reflects the broader context of U.S. governmental failure to uphold treaty obligations, particularly highlighted by the series of treaties that were ignored when they conflicted with American interests like the discovery of gold in the Black Hills. Events like Custer's Last Stand at Little Bighorn showed the willingness of Native American tribes to fight for their land, but even their victories were short-lived. U.S. policies and actions consistently undermined the spirit and letter of treaties such as the Treaty of Fort Laramie and the Treaty of Medicine Lodge Creek.