The graph shows temperatures in Greenland from 500 CE to 1990 CE. A line graph titled Temperature Changes in Greenland. The graph shows Year on the x-axis, from 500 to 1990 and Temperature Changes (in degrees Celsius) on the y-axis, from Colder to Warmer. Coldest temperatures are at the following Years: 650, 850, 1100 to 1200,1350, 1700, and 1850.

What can these data help historians understand about the Viking settlements in Greenland?

that the Vikings enjoyed consistently warm temperatures while they lived in Greenland
that the Vikings were careful to settle in areas that would support year-round agriculture
that colder temperatures starting in about 1300 may have forced the Vikings to leave Greenland
that the Vikings probably arrived in Greenland by about 1000, when the temperatures were cooler