Lobsters and other crustaceans eaten by humans are more likely to contract gill diseases when sewage contaminates their water. Under a recent proposal, millions of gallons of local sewage each day would be rerouted many kilometers offshore. Although this would substantially reduce the amount of sewage in the harbor where lobsters are caught, the proposal is pointless, because hardly any lobsters live long enough to be harmed by those diseases. Which one of the following, if true, most seriously weakens the argument? ['Lobsters, like other crustaceans, live longer in the open ocean than in industrial harbors.', 'Lobsters breed as readily in sewage-contaminated water as in unpolluted water.', 'Contaminants in the harbor other than sewage are equally harmful to lobsters.', 'Humans often become ill as a result of eating lobsters with gill diseases.']