The answer to your question would be that the sentence that uses an in-text citation correctly according to MLA standards is the following one: Naturalists believe that developing the wetlands would do "untold damage to the local envrionment" (McPherson 14). That is, your answer would be B.
The sentence in question is an example of a parenthetical in-text citation in which the name of the author is included in parenthesis after the sentence, along with the page number. It is an MLA paranthetical citation example.
B would be best suited, although D could work in the situation that there are multiple works in the bibliography that are written by McPherson. If it was just one work by him, then it would be B.
