What Do the Authors of South Carolina's Declaration of the Immediate

What do the authors of South Carolina's Declaration of the Immediate Causes of Secession present as the cause of their leaving the Union?

A) the federal government's refusal to respect states' rights
B) the election of a president who received no votes from the southern states
C) the federal government's refusal to endorse the Ostend Manifesto
D) the North's increasing opposition to slavery
E) the Supreme Court's hostility to the interests of slave owners