The Chinese Exclusion Act, enacted in 1882, targeted Chinese immigrants largely due to growing discrimination and racial prejudice against them. The correct reason from the options you've provided is:
They suffered growing discrimination.
Chinese immigrants faced significant hostility and were often scapegoated for economic and social issues in the United States. As their presence in urban areas increased, so did the resentment from some segments of the white population, leading to the perception that they were taking jobs away from American workers. The exclusionary policies were a reflection of broader attitudes of nativism and racism prevalent at the time.