Answer: B. Prohibiting new Chinese immigrants to enter the country.
Step-by-step explanation:
Several social conflicts intensified in the US during the 1870s as the country developed as an industrialized nation. With the widespread economic and insecurity, xenophobic feelings started to grow, especially toward Chinese people. In 1882, Congress voted for the Chinese Exclusion Act, Prohibiting new Chinese immigrants to enter the country. It was the first federal law based on race and class but excused students, teachers, merchants, and diplomats to protect US trade and treaty interests.