Which pull factor accounted for much of Chinese immigration to the United States in the mid-1800s?

Which of these was a primary reason Chinese immigrants came to the United States in the early 1850s?

Catholics immigrated to the Maryland colony in the seventeenth century primarily to —

In the 1840s, thousands of Irish immigrants came to the United States seeking to escape —

Between 1846 and 1855 the population of Ireland decreased by a third, including the approximately 1.5 million Irish immigrants who left for the United States. What was the primary reason for this migration?