Final answer:
The best example of a comparative structure can be found in quote A, which states, "By the end of the second week, in fact, the fairies had covered the entire plot with footprints."
Step-by-step explanation:
The best example of a comparative structure can be found in quote A, which states, "By the end of the second week, in fact, the fairies had covered the entire plot with footprints." This quote compares the progress of the fairies in covering the plot with footprints over a certain period of time.