The federal union is a union of people in which ___________.

A、thenationalgovernmentandstategovernmentreceivepowerfromthepeopleandexerciseauthorityovereachother;
B、thenationalgovernmentandstategovernmentreceivepowerfromthepeopleandexerciseauthorityoverthepeople;
C、stategovernmentreceivespowerfromthenationalgovernmentandexercisesauthorityoverthepeople;
D、thenationalgovernmentreceivespowerfromthestateandexerciseauthorityoverthestate