The correct answer is D) citizens feared that they would take American jobs by working for lower wages.
The reason the immigrants faced challenges in the United States was that citizens feared that they would take American jobs by working for lower wages.
United States citizens did not like the idea of immigration since the very beginning. They have considered that immigrants –due to their desperation for getting a job- would accept less wage in order to perform a job. So U.S. citizens feared that they would take American jobs by working for lower wages. It happened a two hundred years ago with Italian, Irish, Chinese or German immigration as it is happening now with immigration from Central America. The problem now is that there is this idea of fear because more than getting the cheap jobs, immigrants are the cause of insecurity.