A historian is interested in determining whethed a new biography of Franklin D. Roosevelt, the president of the United States from 1933 to 1945, is biased against its subject. Which of the following pieces of evidence woould be most helpful to her?

most people now work in jobs where they do one  kind  of work; they are carpenters, bankers, cooks, mechanics, and so forth. likewise, most  businesses produce  only certainkinds  of  goods  or  services, such as cars, tacos, or gardening  services. this feature of  production  is known as specialization.

you didn't list the options. however, a few communist countries today are: the people's republic of china, north korea, and cuba.