The purchase of the Louisiana Territory led to a pattern of westward expansion through payment, negotiations, and conflict. The United States purchased Florida from Spain with the Florida Purchase Treaty of 1821. Instead of paying Spain a set amount, the United States would pay the $5 million Americans claimed were owed to them by Spain. After Texas declared independence from Mexico, it was annexed by the United States and became an official state in 1845. Another land controversy occurred between Great Britain and the United States, as both countries claimed the Oregon region. The dispute was settled in the 1846 Oregon Treaty, which separated the countries by the line of the 49th parallel. Mexico refused to let the United States buy California and New Mexico, so the two countries eventually went to war. Because the Americans won the war, the United States was able to buy lands in the Southwest in 1848. The United States paid Mexico $10 million for an area of land in the Southwest in the 1853 Gadsden Purchase, stretching its borders from sea to sea.

According to information in the text feature, in what year did the United States officially obtain land with access to the Pacific Ocean?

A) 1821
B) 1845
C) 1846
D) 1848