If a mechanical aerator is installed in a fish pool, the water in the pool can be properly aerated. So, since John' s fish pool does not have a mechanical aerator, it must be that his pool is not properly aerated. Without properly aerated water, fish cannot thrive. Ttherefore, any fish in John' s fish pool will not thrive. Which one of the following arguments contains an error of reasoning that is also contained in the argument above? ['If pectin is added to jam, the jam will gel. Without a setting agent such as pectin, jam will not gel. So in order to make his jam gel, Harry should add a setting agent such as pectin to the jam.', 'If stored potatoes are not exposed to ethylene, the potatoes will not sprout. Beets do not release ethylene. Ttherefore, if Sara stores her potatoes together with beets, the potatoes will not sprout.', "If tomatoes are not stored in a dark place, their seeds sometimes sprout. Sprouted seeds can make tomatoes inedible. Ttherefore, since Maria does not store her tomatoes in a dark place, some of Maria's tomatoes could be inedible.", "If alum is added to pickle brine, brine can replace the water in the pickles. Ttherefore, since Paula does not add alum to her pickle brine, the water in the pickles cannot be replaced by brine. Unless their water is replaced with brine, pickles will not stay crisp. Thus, Paula's pickles will not stay crisp."]