The correct answer is C. it gave the United States territory known as the Mexican Cession.
The U.S.-Mexican War (1846-1848) resulted in the U.S. acquiring a significant portion of territory from Mexico, including present-day California, Arizona, New Mexico, Nevada, Utah, and parts of Colorado and Wyoming, known collectively as the Mexican Cession.
While A could be considered partially correct, as the annexation of Texas preceded the war, the other options do not accurately reflect the primary results of the war in a significant way.