An efficient technique for these four-phrase error-spotting questions is to stitch the phrases into one continuous sentence first, then read it aloud in your head checking only for subject-verb agreement, since that is the most common trap in this format.
Joined together: "However, the advantages of teamwork can be minimized and the benefits increased if members (particularly those who lead them) is aware of the methods for improving performance and making decisions."
Strip out the parenthetical aside "(particularly those who lead them)", since a parenthesis never carries the grammatical weight of the sentence, and the core clause becomes: "if members is aware of the methods...". Read this way, the mismatch is obvious: "members" is plural, but "is" is a singular verb form. The parenthesis was likely inserted to create distance between the subject and the verb, tempting a reader to wrongly agree the verb with the nearer singular-sounding phrase "those who lead them" or simply lose track of the original subject.
Restoring correct agreement gives: "if members ... are aware of the methods for improving performance and making decisions," which belongs to phrase (d), confirming it as the faulty phrase.
The correct answer is option 4, phrase (d).
Identify the part of the sentence that contains an error:
"Neither the manager nor the employees ___ willing to accept the new policy."