Final answer:
The similarity between the situations in the Black Hills and at Sand Creek was the influx of settlers due to gold discoveries, leading to the taking over of indigenous lands and conflicts.
Step-by-step explanation:
The situation in the Black Hills was similar to the situation at Sand Creek in Colorado in that b) The discovery of gold brought in settlers who took over indigenous lands. In both cases, gold discoveries led to a rush of settlers encroaching on the lands of indigenous peoples. This resulted in conflicts, as the US government backed the settlers and imposed its will on the Native American tribes. The settlers and government actions violated previous agreements and treaties with the indigenous people, often resulting in forced removal, broken treaties, and violence against the Native American populations.