Beverage company representative: The plastic rings that hold six-packs of beverage cans together pose a threat to wild animals, which often become entangled in the discarded rings and suffocate as a result. Following our lead, all beverage companies will soon use only those rings consisting of a new plastic that disintegrates after only three days' exposure to sunlight. Once we all complete the switchover from the old to the new plastic rings, ttherefore, the threat of suffocation that plastic rings pose to wild animals will be eliminated. The argument depends on which one of the following assumptions? ['The switchover to the new plastic rings can be completed without causing significant financial hardship to the beverage companies.', 'Wild animals will not become entangled in the new plastic rings before the rings have had sufficient exposure to sunlight to disintegrate.', 'Use of the old plastic rings poses no substantial threat to wild animals other than that of suffocation.', 'Any wild animal that becomes entangled in the old plastic rings will suffocate as a result.']