Integration of the high school in Little Rock finally happened when

In 1957, a federal court ordered integration in Little Rock, Arkansas, public schools. Nine black children were selected for admission to Little Rock Central High School, but local police, by decision of the state governor Faubus, did not allow them to attend classes. After the Little Rock crisis attracted media attention and sparked an international outcry, President Dwight Eisenhower sent federal troops to Little Rock. On September 24, 1,200 soldiers from the 101st Airborne Division from Fort Campbell, Kentucky, were brought into the city. Soldiers accompanied the children on their way to school and guarded them in the corridors. To deprive Governor Faubus of the opportunity to continue to impede integration, the president reassigned the entire 10,000th Arkansas National Guard to Washington. From that moment, African American children began to attend classes.

the answer is B.