Final answer:
The author develops Marian Anderson's involvement in the Civil Rights Movement by highlighting her performances and successes.
Explanation:
The sentence that best states how the author develops the point that Marian Anderson was part of the Civil Rights Movement is option D: She describes Marian Anderson singing at the Lincoln Memorial as well as many of her other successes that were instrumental in the struggle for racial equality.
This sentence effectively portrays the author's method of showcasing Marian Anderson's significant contributions to the Civil Rights Movement through her impactful performances and achievements.
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