Answer:
A- Westward expansion.
Step-by-step explanation:
James K. Polk ran for president in 1844 with a platform that included a commitment to westward expansion. He believed in Manifest Destiny, the idea that it was America's destiny to expand its territory to the Pacific Ocean. Specifically, Polk advocated for the annexation of Texas and the acquisition of Oregon from Britain. As president, Polk pursued these goals and oversaw the Mexican-American War, which resulted in the United States gaining a large portion of Mexico's territory, including what is now California, Nevada, Utah, Arizona, New Mexico, and parts of Colorado, Wyoming, Kansas, and Oklahoma.