The original sentence has an unclear referent. Only the choice with Velma's name clarifies that Velma is indeed the individual who crossed in the middle of the street, as opposed to the taxi driver.

The sentence has a vague pronoun reference. The use of "their" before "prescriptions" is ambiguous because we do not know if "their" refers to the doctors' or the pharmacists' prescriptions. The sentence needs to clarify to whom the pronoun refers, so the best answer choice is the one that does this, "and many pharmacists regularly complain about doctors' prescriptions."

It is unclear if the “him” refers to Kennedy or Nixon. The correct answer makes it clear with whom I agree. 

The use of the simple pronoun "him" is confusing in this sentence, as it is unclear exactly who the pronoun refers to, the subject or some other person. The best way to clear this confusion up is by using the reflexive pronoun "himself" to refer back to the subject. Thus, the correct answer choice is "to pamper himself with nice meals on the road."

This phrase must have a pronoun and a possessive pronoun which refer to all three individuals: "we" and "our."

In the answer choice "she always goes to our favorite restaurant," the pronoun “she” does not agree with the subject of “Sheila, Veronica, and I”—it should be “we.”

In the answer choice "we always go to her favorite restaurant," the possessive pronoun “her” should be “our,” as it refers to a restaurant preferred by all three subjects. Though this sentence could be correct, it is not the best option because “her” is not specified.

In the answer choice "we always went to our favorite restaurant," the verb “go” must agree with the present tense of “spend,” so it is incorrect.

In the answer choice "they always go to their favorite restaurant," the pronouns “they” and “their” exclude “I” as a subject, so it is incorrect.

The use of "him" at the end of the sentence is confusing and awkward, as it is not clear to whom the pronoun is referring. Changing the simple pronoun to a reflexive pronoun allows the pronoun to refer back to the subject of the sentence clearly. Thus, the correct answer choice is "that only benefitted himself."

The sentence is faulty because it uses a pronoun with an ambiguous antecedent. The reader can't be sure who either "they" or "them" is referring to -- the bankers or the computers. The error can be fixed by rearranging the sentence so that "they" is followed by the clarifying subject "bankers."

This is an example of an ambiguous pronoun. The "him" in "to give him away" in the original sentence could be applying to either the dog or the cat, so we must make clear that it is one or the other.

Answer choices "researchers have discovered several additional drugs that, when administered by a health care professional, has helped to reduce the risk of influenza" and "researchers have discovered several additional drugs that, when administered by a health care professional, helps in reducing the risk of influenza" contain subject-verb agreement errors because they use singular verbs—"helps" and "has helped"—rather than the plural verbs required by the plural noun "drugs."

The answer choices containing "they" as opposed to "researchers" are incorrect because they contain an ambiguous pronoun. We don't know to whom "they" refers.

The answer choice "researchers have discovered several additional drugs that, when administered by a health care professional, help to reduce the risk of influenza" is correct because it is the only answer choice that correctly avoids using an ambiguous pronoun and doesn't introduce any subject-verb agreement errors.

In sentences with multiple antecedents in a sentence, it is to be important to be extremely clear with pronoun usage (perhaps even avoiding pronouns altogether in order to avoid ambiguity). In the sentence above, "them" could refer to either "the overseers" or "the workers." The best way to correct the underlined portion of the sentence above is: "it was time for the workers to take a break."