What 1969 Event Became the Most Dramatic Action Taken by Militant

What 1969 event became the most dramatic action taken by militant Indians in the United States?

A) A hostile takeover of a federal building in Washington, D.C., for two weeks
B) Local Indian activists' seizure and occupation of Alcatraz Island
C) Apaches damming of the Colorado River, causing flooding in Colorado
D) Sioux Indians holding South Dakota legislators hostage for twenty-one days