The correct answer is number 4.- Congress was controlled by the Republican Party during his time in office.
The statement that explains why President Kennedy did not succeed in getting a civil rights act passes is because Congress was controlled by the Republican Party during his time in office.
President John F. Kennedy was the first one to purpose the civil rights act but he encountered the opposition of Republican Congressmen in the South. That is why it passed years later under the Presidency of Lyndon B. Johnson as the Civil Rights Act of 1964. The legislation ended with segregation practices in public schools and in the work place.