<span>e. b and c only
As long as a speaker lets the audience know who the author of a study is, and gives a brief overview of their credentials or qualifications, the audience should be able to trust the information that the speaker is presenting, based on their credible research.</span>
A pronoun shift is when you modify the pronoun in the same sentence, then the reader is not able to understand who is the subject of the sentence.
In the exemplified sentence the pronoun inserted incorrectly is <u>they</u>, shifting the initially singular subject "The student" (pronouns he or she) to a plural pronominal form.
When correcting, the writer must evaluate which is the desired pronoun, that fits his subject.:
<em>(Singular form) If the student feels ill, he/she should be sent to the nurse.
</em>
<em>(Plural form) If the students feel ill, they should be sent to the nurse.</em>
So, the pronoun shift that should be circled is They
"This is the second activity in the repetition strategy" indicates that the word revisit would be the best word to use to sum up the idea since repetition strategy definitely suggests revisiting. Something which is repeated is done over again so in the act of re-doing it it means it is also re-visited.
