Step 1 — Read the full sentence with all parts:
(a) However, the advantages of teamwork can be minimized
(b) and the benefits increased
(c) if members (particularly those who lead them)
(d) is aware of the methods for improving performance and making decisions
Step 2 — Check subject-verb agreement:
- In part (c), the subject is clearly members, which is plural.
- Therefore, the verb that follows should also be plural.
Step 3 — Spot the error:
In part (d), the phrase reads: "is aware of the methods..."
- Here, "is" is singular, which does not agree with the plural subject "members."
- The correct verb should be "are."
Step 4 — Correct the sentence:
"... if members (particularly those who lead them) are aware of the methods for improving performance and making decisions."
Step 5 — Conclusion:
Thus, the grammatically incorrect phrase is in part (d).
Final Answer:
The correct option is (D) : d.