Ferdinand Magellan was a P<span>ortuguese explorer sponsored by Spain who tried to sail around the world.
Hope this helps :)</span>
A. is a duty of congress. They can say a law is unconstitutional based in their views on the law but they cant declare one unconstitutional. But the President can declare a law unconstitutional and change it.
International? You really don't give much information but I believe that's it.