Which of These Best Explains the Surge in Immigration into the United

Multiple Choice

Which of these best explains the surge in immigration into the United States from Mexico that began in the late 1870s?

A) the policies of Mexican president Porfirio Diaz
B) new U.S. immigration laws allowing easier entry into the United States
C) an increase in violence and banditry along the Mexican border
D) a series of poor harvests throughout most of Mexico