I believe its B as 'progressive' means <span>favoring or advocating </span>progress, change, improvement, or reform, as opposed to wishing to maintain things as they are, especially in political matters:<span>
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secondary sources are: books, newspapers, pamphlets and encyclopaedias. Secondary sources involve generalization, analysis, synthesis, interpretation, or evaluation of the original information so i would say D. a series of correspondence between former United States presidents Thomas Jefferson and John Adams
A.
Undermine
erode the base or foundation of (a rock formation).
