Their goal was to establish a new colony near Chesapeake Bay. Two years earlier, Sir Richard Grenville had a unsuccessful attempt of this. He had left 100 man to the island and went back to England to get supplies. He brought supplies and 15 more men to stay there until reinforcements could be brought from England.
Before John White leaves he finds the island deserted. With only the bones of one man were found. Less than a month later, Whites daughter gave birth to the first English child born in North America and her name was Virginia
The most likely one that happened was the one where they left the island and traveled to Roanoke. I think this is the most likely because it said they wrote 'CRO' and 'CROATOAN' on two different trees and none of the trees had a cross (which would mean they were in danger). The reason they wrote 'CROATOAN' was probably because they were moving there, and the reason for the buildings being destroyed is probably because they didn't want the Indians to use their building.