Why Are the Riots in American Cities During the 1960s

Why are the riots in American cities during the 1960s best understood as battles?

A) The Department of Defense deployed regular army units to suppress these uprisings.
B) African-American rioters often had received military training in Cuba and Venezuela.
C) Urban blacks saw the predominantly white police force as an occupying army.
D) Rioters frequently employed weapons otherwise only used in military combat operations.
E) Riot squads were organized by the Department of Defense.