Please Help ASAP *ANSWER C IS INCORRECT... :) What is the main idea of this excerpt from Abraham Lincoln’s First Inaugural Address?

I hold that, in contemplation of universal law and of the Constitution, the Union of these States is perpetual. Perpetuity is implied, if not expressed, in the fundamental law of all national governments. It is safe to assert that no government proper ever had a provision in its organic law for its own termination. Continue to execute all the express provisions of our National Constitution, and the Union will endure forever—it being impossible to destroy it except by some action not provided for in the instrument itself.

A. Secession negatively affected the nation’s economy.

B. Secession was a peaceful mode of rebellion.

C. Secession from the Union was illegal.

D. Secession defied the principles of the Confederacy.

E. Secession was the leading cause of the Civil War.

WILL MARK THE BRAINLIEST!