Though Earth' s human population is increasing, it currently uses only a relatively small fraction of the supply of fresh water. Thus, claims that water shortages will plague humankind in the near future unless population growth trends change are simply mistaken. Which one of the following, if true, most seriously weakens the argument above? ['The percentage of fresh water used for agriculture is likely to grow more quickly than is the percentage used for industry.', "Not all of Earth's population will adopt water conservation methods in the near future.", 'Population growth trends are notoriously hard to predict with reasonable accuracy.', "The amount of fresh water available to meet the needs of Earth's population varies significantly from region to region."]