The right answer is b.the lawful sales of semiautomatic rifles.
The US had several Immigration reforms on its history, given that the promise of cheap land and good wages drew millions of immigrants to America. As expect, those waves of immigrants were not always welcomed by Americans, the final answer was to create Immigration reforms. One of the first reforms concerned about foreign radicals invading the United States. In the development of new reforms, the security of borders became one fundamental issue, specially with Mexico. Also, the process of checking the legal status of illegal immigrants, in order to deport those who are not legal in the country. On the other hand, the need for workers also generated a process of seasonal work permits, increasing the supply of workers in specified periods of the year.