In the United States, as of 2009, Hispanics were the largest and fastest growing immigrant group. The correct option among all the options given in the question is option "C". Immigration is one of the reasons that has given the United States of America a great diversity in culture. It is also the main reason behind the population rise in the United States of America. Hispanics are considered the largest minority group in the United States of America. In the year 2013 the number of Hispanics in United States has been calculated to approximately 54 million and it was on the rise.