D: gives you information about many primary sources
These sources offer an analysis or restatement of primary sources. They often try to describe or explain primary sources. They tend to be works that summarize, interpret, reorganize, or otherwise provide an added value to a primary source.
Examples of Secondary Sources:
Textbooks, edited works, books, and articles that interpret or review research works, histories, biographies, literary criticism, and interpretation, reviews of law and legislation, political analyses, and commentaries.
Hope this helps you better to understand the meaning of secondary sources
