Final answer:
Approximately 15% of Oklahoma residents fled the state during the Great Depression and Dust Bowl years due to economic hardship and environmental catastrophe. The correct option is 3.
Step-by-step explanation:
During the Great Depression and Dust Bowl years, a significant percentage of Oklahomans were forced to leave the state in search of better living conditions and employment. The crisis was particularly severe as it disrupted both urban and rural economies. According to historical records, approximately one in six Oklahoma residents, or around 15%, abandoned the state during the 1930s.
This mass exodus included not only farmers but also white-collar professionals whose livelihoods were interconnected with the agricultural sector. Many of these individuals, including a large population of mixed-blood Native people, moved westward to California, where they faced harsh conditions and competition for scarce jobs.