The transcontinental railroad was completed in
a. 1861.
b. 1840.
c. 1869.
d. 1901.

The correct answer is C. The Transcontinental Railroad was completed in 1869.

Explanation:

The Transcontinental Railroad was completed with the famous Golden Spike ceremony held on May 10, 1869 in Promontory, Utah, creating a nationwide mechanized transportation network that revolutionized the population and economy of the American West, as it connected Nebraska with California.

labor leaders and organizations had the power to demand it.

explanation:

workers got a five-day workweek because the bcea protects and respect the rights of the employees. labor leaders and other groups demanded it.

option d is correct. corroborated sources of historical evidence   is necessary to validate a claim about an event in history.

historians tend to use written sources, but audio and visual materials as well as artifacts are important objects that supply information to modern historians.

historical sources are usually divided into two categories: primary and secondary sources. depending on the historian's intent, some sources shift their designation. determining what type of sources toimplement, and the level of credibility and reliability of those sources, is a significant step in critical thinking for the historian.

explanation: