Final answer:
The correct item that would have to be disclosed to prospective buyers by the listing broker is a defect existing in the property being offered.
Step-by-step explanation:
The correct answer is B. A defect existing in the property being offered.
The listing broker is responsible for disclosing any defects in the property to prospective buyers.
This is because buyers have a right to know about any issues that may affect the value or safety of the property they are considering purchasing. By disclosing defects, the listing broker helps ensure that buyers have all the necessary information to make an informed decision.