Question

in the 1860s, tensions in colorado between american indians and white settlers led to a massacre at
little bighorn.
sand creek.
wounded knee.
pikes peak.

Explanation:

In the 1860s, tensions between American Indians and white settlers in Colorado led to the Sand - Creek Massacre. Little Bighorn was in Montana in 1876. Wounded Knee was in South Dakota in 1890. Pike's Peak is a mountain, not a site of a massacre related to these tensions.

Answer:

Sand Creek.