The answer is B, because the cause of the Sudan civil war was a clear split between north and south Sudan. You can also see other examples like the unhappy Kurdish minorities in Syria, Turkey, and Iraq.
The reliance could be seen on how we acquire our military draft.
For example, countries such as Russia and south Korea implemented a mandatory military services for all adult men. (they're require to served at the military for around 1-2 years).
United states on the other hand, does not implement such mandatory military draft. All of our forces were acquired through voluntary methods without government force.
Since the nature of war has changed, voluntary method is more than enough since war that conducted on modern time would most likely relied on mass destruction weapons or advanced vehicles.
The Star Spangled Banner was written during the defense of this place during the War of 1812. answer is Fort McHenry
