Answer:
C. While foreign migrant workers are forced to leave the United States after a period of time, migrant workers from within the United States are able to stay and work indefinitely.
Step-by-step explanation:
As per the question, the contrast that the author establishes between "the migrant workers who arrived from the United States and the ones who came from other Foreign nations" is that 'the foreign workers were deliberately compelled to depart from the U.S. post a specified time-period while migrant workers from the U.S. itself were given the permission to stay without any restrictions.' The Visa limitations further substantiate this discriminated behavior that clearly displays the distinction in the behavior towards the two types of farm workers just because of their country of origin and the foreign workers had no other option instead of leaving when said. Thus, option C is the correct answer.