The Roman Republic was certainly a thriving democracy by the standards of its time, but it should be noted that women, slaves, and many men were not allowed to vote.
The president cannot make laws. Only the legislative branch (the Congress) can make laws. But the president can certainly veto laws and make official appointments. And as commander-in-chief of the military, the president also oversees the armed forces. So the only power in your list that the president does NOT have is to make laws.
Answer:
D, demonstrating American strength to the world.
