What country left and rejoined the african union

In 1956, people in demanded that soviet troops to be removed as the part of a call for democratic reforms

How did the completion of the transcontinental railroad change the lives of american citizens? a-it increased the wealth of all americans and enabled them to travel more.b-it made cross-country travel too expensive for ordinary americans.c-it decreased the safety of americans who moved to settle the plains.d-it shortened travel time between the east and west for all americans.

How should the student cite this source using mla citation format?