Final answer:
Referral fees must be disclosed in professional settings even if money isn't exchanged to ensure transparency and prevent conflicts of interest.
Step-by-step explanation:
When it comes to the disclosure of referral fees, the ethical and often legal requirement is that they must be disclosed to the involved parties, even if no money ($) is actually exchanged. This transparency helps to maintain trust and avoids conflicts of interest.
Therefore, the correct answer is: C) Referral fees must be revealed even if $ isn't exchanged. It is essential for professionals to adhere to this practice in jurisdictions where such rules are mandated, as is commonly the case in real estate, legal professions, and other business transactions where referrals can influence decisions.