Phytoremediation is the use of plant growth to purify pollutants from soil, water, or air. suppose that a crop of brake ferns can remove 151515 milligrams (\text{mg})(mg)left parenthesis, m, g, right parenthesis per square meter of a particular pollutant from the soil in 202020 weeks. after 202020 weeks, the ferns are harvested and a new crop is planted. if ccc represents the number of crops of brake ferns needed to phytoremediate soil contaminated with 170\,\text{mg}170mg170, space, m, g per square meter of the pollutant down to healthy levels of 5\,\text{mg}5mg5, space, m, g per square meter, which equation best models the situation? choose 1 170-20c=5170−20c=5170, minus, 20, c, equals, 5 170+20c=5170+20c=5170, plus, 20, c, equals, 5 170-15c=5170−15c=5170, minus, 15, c, equals, 5 170+15c=5170+15c=5170, plus, 15, c, equals, 5