Most small children are flat-footed. This failure of the foot to assume its natural arch, if it persists past early childhood can sometimes result in discomfort and even pain later in life. Traditionally, flat-footedness in children has been treated by having the children wear special shoes that give extra support to the foot, in order to foster the development of the arch. Which one of the following, if true, most calls into question the efficacy of the traditional treatment described above? ["Although most children's flat-footedness is corrected by the time the children reach puberty, some people remain flat-footed for life.", 'Many small children who have normal feet wear the same special shoes as those worn by flat-footed children.', 'Flat-footed children who do not wear the special shoes are as likely to develop natural arches as are flat-footed children who wear the special shoes.', 'Some children who are not flat-footed have hip and lower leg bones that are rotated excessively either inward or outward.']