Final answer:
Option D, preserving the Angel Island Immigration Station, is NOT an example of discrimination against detained Chinese immigrants; other options are examples of unfair treatment based on discriminatory laws like the Chinese Exclusion Act of 1882.
Step-by-step explanation:
The option that is NOT an example of discrimination against the detained Chinese immigrants at Angel Island is D. preserving the Angel Island Immigration Station. This action does not represent an act of discrimination but rather a conservation effort of a historical site. In contrast, A. throwing them in barracks and holding them against their will, B. interrogating them for long periods at a time, and C. keeping them in sparsely furnished buildings are all examples of the discriminatory practices and harsh conditions that Chinese immigrants faced during their detainment on Angel Island, where they were treated unfairly due to the Chinese Exclusion Act of 1882 and resulting policies.