which condition enabled the virtual enslavement of Asian Americans in the late 19th century.?

a. Segregation under the separate but equal doctrine.
b. Inability to apply the 13th amendment in certain states.
c. Distinctions between the rights of citizens and non-citizens.
d. Refusal of the government to protect Asian Americans from their employers.

d. Refusal of the government to protect Asian Americans from their employers.