Answer: a) the inalienable rights to life, liberty and the pursuit of happiness
Explanation:
The State of Southern Carolina began it's Secession Declaration by stating that... "<em>deems it due to herself, to the remaining United States of America, and to the nations of the world, that she should declare the immediate causes which have led to this act</em>". This invalidates option D because they believe themselves obliged to declare their reason for seeking independence.
The Declaration then speaks on the notion that Governments are established by humans to aid them to certain ends. End which if not met, constitute a just cause to remove the Government from power. This invalidates option B.
In the last part of the Declaration, South Carolina alluded to its reasons for seeking independence being that the Northern Non-slave states had violated statutes that required them to return slaves who escaped from a slave state. This invalidates Option C.
Option A was never alluded to in the Secession Declaration of South Carolina and little wonder why. As a state that was in support of slavery, to maintain that all people had<em> the inalienable rights to life, liberty and the pursuit of happiness, </em>they would have been invalidating the institution of slavery and so they abstained from emphasising it.