In Literature, Subject is referred as a topic. The theme is the opinion expressed on the subject. So basically, both are entirely different. Hope this answers your question.
After reading the passage, I've been battling between answers A. and C. I have decided that the best choice would be A, since the passage clearly states that it is up to the people to protect their rights. Hope this helps! ^_^
The correct answers are:
“The Constitution refers to slaves as ‘persons held to service in one State’”
“Acts of Congress as prohibited slavery and involuntary servitude within that part of the Territory of Wisconsin . . . were constitutional and valid laws.”
