The union pacific, which laid railroad tracks westward from omaha, nebraska, hired many irish workers. the central pacific, which laid tracks eastward from california, employed thousands of workers from
a. africa
b. england
c. china
d. india

  C. China.

Explanation:

  The construction began officially in 1863 planned by Theodore  Judah and authorized one year earlier by the Congress. But it was not until 1865 that the construction began more efficiently. The head of the workforce, James Harvey Storbridge, hired Cantonese workers. By 1868 the Chinese workforce grew up to 12,000 laborers that constituted 80% of the entire workers.

  I hope this answer helps you.

equal area projections

equal-area projection. a projection in which regions on the earth's surface that are of equal area are represented as equal.