The broker has a single agency relationship with the seller.

In Massachusetts, when a broker represents the seller, the buyer is treated as a customer (not a client). While the broker owes fiduciary duties to the seller, they also have a duty of honest dealing and disclosure of material defects to customers.

A leaky roof in heavy rains is a material defect that affects the property’s value and safety. The broker must disclose it regardless of agency relationship.

The seller’s urgency to move (A) and dislike of a neighbor (D) are not material facts.

A positive feature like a lake view (B) may be marketed but is not a required disclosure.

Thus, the correct answer is C: leaky roof.