Under the Constitution, Which of the Following Is True About

Under the Constitution, which of the following is true about the responsibility for common defense and security?

A) It is a shared responsibility between the states and the federal government.
B) It is solely the responsibility of the national government.
C) The federal government sets general policies, but a supermajority of states can disapprove of any policies.
D) The states would continue to handle these policies because the national government would take responsibility for regulating commerce.