Cesar chavez worked to improve the lives of workers.

The answer would be immigrant farm workers.

Cesar Chavez was the first activist who has made the first labor union for farmers. He was one of the founders of United Farm Workers and fought for the health benefits for many immigrant workers in the late 1960’s. Chavez was able to help farmers have clean water, protections gears when spraying pesticides and a better pay. 

i am pretty sure it is a

i would think the answer is between b and d i would say d sorry if wrong