The correct answer is D. Louisiana Purchase.
Step-by-step explanation
The Louisiana Purchase was a commercial transaction carried out at the beginning of the 19th century in which the First French Consul of the time named Napoleon Bonaparte sold about 2.1 square kilometers of his territory in North America to the United States. This purchase of territory was made by President Thomas Jefferson, who considered it essential to have possession of Louisiana since he considered it a strategic point for the commercial river transport of Americans to the port of New Orleans. So, the correct answer is D. Louisiana Purchase.