题目选项分析

Lead water main pipes deliver water to homes and businesses all over the city of Redmond. Because of health concerns related to lead, specially trained workers are required to repair the water main pipes, and without repairs, the water main pipes would eventually cease to deliver water effectively. Therefore, taxpayers in the city of Redmond must continue to provide funds to train workers to repair lead-containing materials safely.

Which of the following, if true, would most seriously weaken the argument above?

【选项】Although lead water main pipes are a necessary part of the delivery of water in Redmond, some residents also obtain a portion of their water from wells.