As there are not options included with this question, it is difficult to answer it precisely. Hitler blamed many different people for the struggles of Germany.
Jews were the most affected both by this belief and by the Holocaust. However, Hitler also targeted other groups, such as communists, homosexuals, Romani people, and other minorities. He also believed that much of the blame for Germany's social and economic problems should be directed towards the West, due to the "unreasonable" terms of the Treaty of Versailles.