When might an author appropriately change styles? select one: a. when the author begins to support the thesis expressed in the previous paragraph b. at any time the author wishes c. when the author's purpose or mood changes d. when the author reaffirms prior knowledge and experience

Most commonly "C", because they would want the reader to understand that something is different. Yes, they can change the style whenever they want to, but it would be more meaningful if they did it for a reason.

MLK is equating segregation and discrimination to slavery; he's saying that the manacles of segregation and the chains of discrimination are just as strong, and just as wrong, as the literal manacles and chains of slavery. His point is that any black discriminated against and segregated is still as good as enslaved.

Explanation:

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-A Helping Friend