Final answer:
The commission offered to cooperating firms must be disclosed in Section D - Broker Compensation of the WB-1 Residential Listing Contract.
Step-by-step explanation:
The section in the WB-1 Residential Listing Contract that requires licensees to disclose the commission offered to cooperating firms is Section D - Broker Compensation. This section outlines the terms of compensation that the listing firm agrees to pay to any cooperating brokerage firm for bringing a buyer who purchases the property. It is crucial for transparency and ensures that all participating parties are aware of the commissions involved.