The correct answer is A) by providing land grants for building tracks.
The government aided the expansion of the railroad industry during the mid- and late 19th century by providing land grants for building tracks.
With the Pacific Railroad Act of 1862, the federal government authorized two companies to connect the East of the United States to the West. Those companies where the Central Pacific and the Union Pacific, and they built the Transcontinental Railroad. One portion of the railroad started in Sacramento, California to the East, and the other started in Omaha, Nebraska, to the West, until the finally met each other in Promontory, Utah, on May 10th, 1869.