Use the graph below to determine the range of values in which the threshold level of this pollutant lies. Dose-response curve shows ten percent of the population died when exposed to thirty milligrams of pollutant A per kilogram of water. Twenty percent of the population died when exposed to thirty-eight milligrams of pollutant A per kilogram of water. Forty percent of the population died when exposed to forty-two milligrams of pollutant A per kilogram of water. Fifty percent of the population died when exposed to forty-five milligrams of pollutant A per kilogram of water. One hundred percent of the population died when exposed to one hundred milligrams of pollutant A per kilogram of water. Between 0 and 10 mg/kg Between 10 and 20 mg/kg Between 40 and 50 mg/kg Between 50 and 60 mg/kg