The most reasonable conclusion that modern historians can draw from the provided evidence is:
Analysis of the cracks in the walls of Hisarlik may change conclusions about the site.
This conclusion acknowledges that recent scientific investigations, such as the examination of the cracks in the walls, could provide new insights into the historical events that might have affected the city, including the possibility of earthquake damage. It implies that our understanding of the site and its significance may evolve as new evidence is analyzed.