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.

The sentence implies that a single female author wrote the Scivas; however, the first clause mentions two women. To resolve the potential ambiguity that "her," which could refer to either Teresa or Hildegard, would introduce, the name of the author must be used rather than a pronoun. "They," which is commonly used in vernacular English to refer to a subject whose gender is either unknown or not specified, is only used to refer to plural antecedents according to the strict rules of standard written English. Finally, as only one work (the Scivas) is mentioned in the passage, the pronoun referring to it must also be singular.

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.

The correct choice is, "The company bought a new machine which had a reputation for incredible efficiency." All of the other sentences are ambiguous and confusing because the pronoun "its" could refer to either the company or the machine as it is used here. The use of "which" clears the confusion, since English grammar dictates that the antecedent of "which" and other relative pronouns come directly before the pronoun.

The best conveys the idea of this sentence is: "Though the parents found lecturing unpleasant, they lectured the children." The other choices are vague, since the pronouns used make it unclear as to who finds the lecturing unpleasant - the children, the parents, or both? It is also possible that no one specifically considers the lecturing unpleasant, but the sentence is making a statement that lecturing in general is unpleasant. The choice "Though the parents found lecturing unpleasant, they lectured the children" is very specific as to who finds the lecturing unpleasant and why.

This sentence contains an ambiguous pronoun. A reader would have no idea to whom "them" refers in this sentence. It is always important to clarify who or what the subject/object is before you are able to refer to it using a pronoun. The correct choice is, "with her friends."

The word "it" in this sentence is ambiguous. In this situation, it is possible for the "it" to refer either to the car or the part installed. Take, for example, that he installed a new radio or speakers in his car. It is entirely possible that the car would be able to work when these components are not working and vice versa. Perhaps while installing the radio/speakers, this person accidentally cut a wire that was vital to some other electrical components of the car. It is possible that the car may not start fully (i.e. to be able to drive), but perhaps the radio might still turn on - at least for a bit. So, it is important to clarify this; the best choice is, "the part did not work properly" since it is the only choice that is not vague.

This sentence contains an ambiguous pronoun. The word "it" could easily refer to the dog or the park in English. The choice that fixes this issue is, "his dog to the park, which was very big" because English grammar dictates that a relative pronoun (which) come directly after the word it modifies.

"Who" is not appropriate because this pronoun is only reserved for humans in English, and "that" is inappropriate because the semicolon before it dictates that both clauses must be independent (any phrase that follows "that" is dependent).