Fishery officials are still considering options for eliminating Lake Davis' s population of razor-toothed northern pike, a fierce game fish that could threaten salmon and trout populations if it slips into the adjoining river system. Introducing pike-specific diseases and draining the lake have been ruled out. Four years ago, poison was added to the lake in order to eliminate the pike. This outraged local residents, because the water remained tainted for months and the region' s tourism economy suffered. Which one of the following is most strongly supported by the information above? ["Salmon and trout populations in the Lake Davis area are essential to the region's economy.", 'The poison added to the lake four years ago was not successful in ridding the lake of the pike.', 'Four years ago was the only time that poison was used against the pike in the lake.', "Draining the lake would not cause the region's tourism economy to suffer."]