The correct answer is John Dollard.
The psychologist John Dollard argued that the roots of prejudice in individuals lie in their frustrations and problems. These frustrated individuals, blame other races or social groups for their problems, and it manifests as prejudice. For instance, in the United States, if a man has prejudiced beliefs about Asian Americans, it could be because, he is frustrated about lack of job opportunities that he feels are due Asian Americans "stealing" all the jobs.