Final answer:
Contract laborers were taken to Hawaii primarily for agricultural development, to work on sugarcane plantations after economic agreements with the United States boosted the sugar industry.
Step-by-step explanation:
The primary reason contract laborers were taken to Hawaii was for agricultural development, specifically for the growing and harvesting of sugarcane on plantations. The need for labor intensified after economic treaties allowed Hawaiian sugar to be sold in the United States duty-free, leading to a boom in the sugar industry that was dominated by American planters. This demand increased even further when the Hawaiian economy crashed due to dependence on the American market, resulting in high unemployment among the immigrant workers.