Answer:
Principle of change.
Step-by-step explanation:
CMA is an acronym for comparative market analysis and it can be defined as an estimate of the value of a house based on the market value of similar houses that were sold in the immediate area where it's located. Thus, it's a tool used by real estate agents to determine or measure the value of a property for a seller.
In this scenario, Amelia's agent informed her that the valuation of eight years ago is no longer accurate.
Hence, the principle of value that is driving her agent's opinion is a principle of change.