Why did the United States want to get control of the city of New Orleans?

Why did the United States want to get control of the city of New Orleans?
 
  A) The geography and climate of New Orleans allowed cultivation of cash crops.
  B) New Orleans provided a means of transportation from the Gulf of Maine to present-day Minneapolis, Minnesota.
  C) New Orleans was a vital port at the mouth of the Mississippi River, which was the country's main north-south inland waterway.
  D) Huge deposits of gold were discovered in New Orleans along the Mississippi River.
  E) The United States could never guarantee control of Lake Pontchartrain unless it controlled New Orleans as well.