Neuroscientists subjected volunteers with amusia -- difficulty telling different melodies apart and remembering simple tunes -- to shifts in pitch comparable to those that occur when someone plays one piano key and then another. The volunteers were unable to discern a difference between the tones. But the volunteers were able to track timed sequences of musical tones and perceive slight changes in timing. The statements above, if true, most strongly support which one of the following hypotheses? ['Amusia results more from an inability to discern pitch than from an inability to discern timing.', 'The ability to tell melodies apart depends on the discernment of pitch alone and not at all on the perception of timing.', 'People who are unable to tell pitches apart in isolation are able to do so in the context of a melody by relying upon timing.', 'Whereas perception of timing can apparently be learned, discernment of pitch is most likely innate.']