Answer: The right answer is the D) He researched migrant workers.
Explanation: Although as a young man he worked in nearby farms and among migrant workers, Steinbeck never was one of them. That experience gave him, nevertheless, first-hand knowledge of the harsh and extreme living and working conditions that those workers had to endure, as well as a genuine feeling of compassion and sympathy towards them. But The Grapes of Wrath was specifically based on a series of newspaper articles about migrant workers that he penned and that were published in 1936 in the San Francisco News under the title "The Harvest Gypsies." In order to write those articles, Steinbeck visited the camps, talked to some of the migrant workers and went through the reports that recorded their daily, and arduous, activity, as well as their sorrows, in great detail.
