B). More information about the Works Projects Administration during the 1930s.
Explanation:
A sidebar is characterized as a brief text that primarily functions to provide additional details or information regarding a subtopic in an article(particularly non-fiction).
As per the question, the sidebar providing 'significant additional details concerning Works Projects Administration during 1930s' would be most adequate to be included in the 'Years of Dust' as it displays the crucial aspects of American history associated with the catastrophetitled'Dust Bowl' and people's struggle to survive in that antagonistic environment. Therefore, <u>option B</u> is the correct answer.
