The correct answer is c. to find work
In 1800s China was having a hard time, the Opium War destabilized the Chinese economy, it caused food scarcity, a devastated economy. Jobs were hard to find.
At the same time, there was the discovery of gold in California made America the perfect place to find a job.
When the gold rush and the railroad was built, Chinese immigrants found jobs such as farmhands, gardeners, domestics, and railroad workers. The built of the Transcontinental Railroad hired many Chinese immigrants to work.