The author’s main purpose is to ______.
A.criticize the emphasis on social standing in discussions of the assimilation of Puerto Ricans in the United States
B.support the thesis that assimilation has not been a benign process for Puerto Ricans
C.defend a view of the assimilation of Puerto Ricans that emphasizes the preservation of national culture
D.indicate deficiencies in two schools if thoughts in the assimilation of Puerto Ricans in the United States