Writing 101 or writing teqnique
In order to try to ensure a feeling of safety
Even though all of the above reasons may be critical pull factors, we could safely lean towards option B, <em>higher wages</em>, as the most indicative answer. Mexicans did not necessarily get better jobs than they had back in their native country, where they may even have been skilled and educated professionals; in fact, wages may have been significantly higher in comparison to their earnings at home, allowing them for having a better quality of life and affording medical care, which tends to be expensive in the USA. Education is not necessarily free -especially at its highest levels, which would help migrants and their offspring to still further improve their quality of life- but then again, higher wages could open the possibility of accessing some private higher education.
The Black Death or plague hit Europe not long after the fall of Rome.