Who was the president who sent federal troops to Arkansas to prevent violence after a federal court ordered the Little Rock schools to be integrated?

The correct answer should be Dwight D. Eisenhower.

He was the one who signed the Civil Rights Act of 1957 into power, which enabled him to send armed forces to integrated schools in Little Rock. Uprisings were growing there because people still believed in segregation and didn't want their kids to go to the same school as black kids. This is why the President had to do something about it.