How Did the United States Gain Unrestricted Access to the Mississippi

How did the United States gain unrestricted access to the Mississippi River and New Orleans?

A) by sending 3,000 regulars and Kentucky militiamen across the river into Spanish territory.
B) by signing an alliance with France against Spain.
C) by purchasing New Orleans from the French.
D) by blockading the entrance to the Mississippi and starved the city into submission.
E) by negotiating the Pinckney Treaty with Spain.