Answer:
This best illustrates: plasticity.
Step-by-step explanation:
Our brains possess the amazing ability to change and adapt when we learn something, or even to find new paths and connections when they suffer some type of damage. That ability is called neuroplasticy, or simply plasticity.
When our brains find new paths or move functions from an area that is damaged to an undamaged area, that is called functional plasticity. The type of plasticity described in the question, concerning the pianists, is called structural plasticity. It means the pianists' brains actually changed their structure as a result from learning and practicing to play the piano. Their auditory cortex is larger than what it would be in other people due to their learning.