What is the purpose of the National Defense according to the text?

I- To guarantee the survival and permanence of the State, including its integrity, unity, and autonomy to act internally and free from any subordination in the external sphere.
II- To maintain the inviolability of the country's sovereignty and independence and the absolute exercise of its freedom of action.
III- To face disasters or accidents caused by natural phenomena or by the effects of an internal or external war conflagration.
a) Only I is correct.
b) Only II is correct.
c) Only III is correct.
d) I, II, and III are correct.