Which of the following has NOT been demonstrated through scientific research? (Note: NOT) a. Rats raised in enriched environments have more synapses than rats raised in impoverished environments. b. Kittens deprived of visual stimulation in one eye early in life become permanently blind in that eye. c. After listening to classical music, college students show increased performance on some tasks. d. Young infants exposed to classical music show higher cognitive performance in preschool.