Snowmaking machines work by spraying a mist that freezes immediately on contact with cold air. Because the sudden freezing kills bacteria, QuickFreeze is planning to market a wastewater purification system that works on the same principle. The process works only when temperatures are cold, however, so municipalities using it will still need to maintain a conventional system. Which of the following, if true, provides the strongest grounds for a prediction that municipalities will buy QuickFreeze's purification system despite the need to maintain a conventional purification system as well? ['Conventional wastewater purification systems have not been fully successful in killing bacteria at cold temperatures.', "During times of warm weather, when it is not in use, QuickFreeze's purification system requires relatively little maintenance.", 'Bacteria are not the only impurities that must be removed from wastewater.', 'Many municipalities have old wastewater purification systems that need to be replaced.']