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<p>Choice (C) employs restrictive apposition; choice (D) may either be attempting to employ a participial phrase or non-restrictive apposition. </p>
<p>Let’s define some of these terms:</p>
<p>Appositive phrases occur when two or more nouns are adjacent to each other; the preceding noun typically modifies the succeeding noun. Non-restrictive appositives are ones in which the second of the two nouns comprehensively modifies the preceding noun, as in:</p>
<p>“My best friend, Bob, went to the store.” The commas around “Bob” are necessary because one is not restricting “best friend”; there is only one best friend.</p>
<p>“I love my wife, Susy.” The commas are necessary to indicate non-restriction; “I” only has one wife.</p>
<p>Restrictive appositives are not offset with commas, as in:</p>
<p>“My friend Bob went to the store.” Presumable, the speaker has more than one friend; thus, “Bob” is restrictive, and commas are not needed.</p>
<p>“American poet Susy is happy.” There is more than one American poet; thus, “Susy” does not comprehensively modify “American poet.”</p>
<p>Choice (C) is correct in its omission of commas: there is more than one African American writer and teacher.</p>
<p>Choice (D) is incorrect as a restrictive appositive for the same reason; commas are used only when there is no restriction. Moreover, the commas would have to surround the modifying noun; there is only one at the beginning of the phrase.</p>
<p>Choice (D) is incorrect as a participial phrase. Participial phrases are adjectivial phrases that modify nouns, as in:</p>
<p>“Being tired and hungry, Bob went home.”</p>
<p>“Feeling bored, Bob is not a fun guy.”</p>
<p>“Being” and “Feeling” are adjectives here; they are verbs being used as participles. Choice (D) does not have a participle.</p>