Migrant farm workers in the united states faced many hardships in the 1960s, including
broken treaties with the united states.
poor pay and discrimination.
lack of protection for their lands.
being denied their full rights as us citizens.

The answer may be either B. broken treaties with the United States. or D. being denied their full rights as US citizens., to be B makes more sense

In 1960s, the Bracero program was ended because of the abuses to which Bracero workers were subjected. The enforcement of regulations on Bracero wages, housing, and food charges was negligible; to this day, Bracero workers who worked in the fields are still fighting to get the 10% mandatory reductions from their wages that they were supposed to receive when their contracts ended and they returned to Mexico.

So the answer for the question above is poor pay and discrimination.