Final answer:
The factor that should NOT be used to determine which adviser to hire is the adviser's favorite color. The correct answer is d).
Step-by-step explanation:
The correct answer is d) Favorite color of the adviser. When hiring a financial adviser, it is important to consider their qualifications and credentials, as this demonstrates their expertise and knowledge in the field. Fee structure is also a crucial factor to consider, as it affects the cost of the services provided. Personal recommendations can provide insights into the adviser's track record and performance. However, the favorite color of the adviser is not relevant or indicative of their ability to provide sound financial advice.