A scientific research institution in a country tracked the mental health of more than 10,000 people born in the 1950s and 1970s, during which they tested their language skills, space perception and induction ability between the ages of 13 and 18. During this period, adolescents whose language ability is far below the level of their peers have a higher risk of developing a mental illness such as schizophrenia in adulthood. Researchers believe that the level of language competence in adolescence will be an important indicator for predicting mental illness in adulthood. Which of the following, if true, can challenge the above view? ['Abnormal levels of hormone secretion in adolescence, affect brain development and cause sluggish language development.', 'Adolescents with schizophrenia develop inductive skills more slowly than their language skills.', 'Many mentally healthy brain tumor patients often experience problems with delayed language development in their adolescents.', "Proper education can significantly improve adolescents' language skills, but it has little effect on the elderly."]