Theodore D. Judah, the engineer of the Sacramento Valley Railroad, became obsessed with the desire to build a transcontinental railroad. In 1860 he approached Leland Stanford, Collis P. Huntington, Mark Hopkins, and Charles Crocker, leading Sacramento merchants, and soon convinced them that building a transcontinental line would make them rich and famous. . . . The Railroad Act of 1862 put government support behind the transcontinental railroad and helped create the Union Pacific Railroad, which subsequently joined with the Central Pacific at Promontory, Utah, on May 10, 1869[.] — Library of Congress What was the ultimate motivation behind the development described in the text? A. improving relations between the United States and European powers through trade expansion B. enabling the United States to spread democracy throughout the Americas C. realizing the Manifest Destiny of the United States by connecting the East and West Coasts D. expanding economic opportunities for American Indians in the United States

C. realizing the Manifest Destiny of the United States by connecting the East and West Coasts