One of Douglass' main complaints was the fact that the Constitution did not seem to treat White people and African Americans in the same way. While White Americans receive all the benefits of citizenship, the Constitution did not protect the rights of African Americans, as could be seen in the case of slavery. However, this was remedied, to a large extent, by the passage of the 13th Amendment in 1865. The passage of this amendment abolished slavery and involuntary servitude.
The answer is D. physical or mental ability. "ADA" means "American Disabilities Act", which has been applied to prohibit discrimination upon disabilities.
