During the Rodney King Trial, the People of Los Angeles

During the Rodney King trial, the people of Los Angeles were at a heightened state of stress and frustration, especially the African American population. When the police officers accused of brutality against King were found not guilty, the city erupted into a full-scale riot. The not guilty verdict would qualify as being a(n) ________.

A) background condition
B) precipitating event
C) ultimate cause
D) environmental stimulus