Ashley owns a piece of vacant real estate through which a small river runs. ashley hires warren, a licensed real estate broker, to list the property for sale and sell the property. while inquiring in the neighborhood, ashley's neighbor lenny tells warren that a chemical plant upstream has polluted his property and that warren should have environmental engineers test ashley's property as well. warren does not tell ashley about lenny's suggestion. warren manages to find a buyer for ashley's property in martha. it is later discovered that the property martha bought from ashley is polluted. what important agent's duty has warren failed to perform?