In the year 1869, the first transcontinental railroad was finished. The correct option among all the options given in the question is option "B". The construction of
the railroad started in the year 1863 and finished in the year 1869. It was a
1907 mile continuous railroad that connected Pacific coast of San Francisco Bay
with the Eastern U. S. rail network. The railroad was actually built by three
private companies of the United States. The railroad was opened for traffic on
10th of May in the year 1869.
