I think it's b. I think so.
Answer:
Railroads
Explanation:
Immigrants from China worked mostly as agriculture laborers on railroad construction.
The right answer for the question that is being asked and shown above is that: "D. at least 30 years old, at least nine years a U.S. citizen, and a resident of the state chosen to represent." The qualifications for U.S. Senate as described in Article I of the Constitution includes <span>D. at least 30 years old, at least nine years a U.S. citizen, and a resident of the state chosen to represent</span>