The volcanic eruption that entombed Ceren more than 1400 years ago began when lava pushed its way close enough to the surface to create a great explosion of steam and ash that was centered just north of the village. The archaeologists have not found the remains of any human beings killed by the eruption in Ceren, suggesting that they had enough warning to flee. The eruption buried Ceren in a layer of ash 4 to 6 m (13 to 20 ft) deep over a period of a few days.
One of the most striking of the conclusions drawn from the Ceren site is that the people of this ancient village lived more comfortably than average Salvadorans do today. Ceren's architecture, crafts, and agriculture were surprisingly sophisticated and varied. They ate a rich variety of foods, had spacious, well-ventilated living and working quarters, and lavishly decorated many of their ceramic items. Yet Ceren was an average farming village, not a seat of the ruling class or a regional center of commerce, archaeologists said.
The village of Ceren was rediscovered in 1976 when a bulldozer operator knocked into the wall of one of the structures. Grasses that made up the thatched roof of the dwelling were still preserved, leading an archaeologist to conclude that the structure was recent. After two years, anthropologist Payson D. Sheets of the University of Colorado at Boulder discovered the antiquity of the structures when he dated a sample of thatch to about 1400 years ago.
Sheets was able to survey the site for only a few years before the civil war in El Salvador made it too dangerous to continue. The archaeologists left the site, located northwest of San Salvador, the capital, in 1980 and did not return until 1989. Since then, archaeologists led by Sheets have returned each year.
As of spring 1997, they had digged 12 buildings, including a community hall, living quarters, kitchens, storerooms, a religious hall, a sauna, and even a small building believed to be the workplace of a shaman (a priest who uses magic). The smallest objects of daily life were preserved, sometimes as actual organic matter such as seeds or stems, sometimes as impressions in the ash such as that of a cornstalk or a squash. By sending radar signals through the ground in order to detect buried objects, archaeologists in 1994 located 22 additional structures still buried in ash.
Archaeologists at the site have found the remains of animals including dogs, deer, and a duck tied to a pole. All that remains of the people of Ceren, however, are their footprints, and a few teeth, believed to have been tossed on a roof for good luck. When the teeth were found, workers told Sheets that throwing teeth on the roof is a tradition still practiced by some people in rural El Salvador today.
When the author says that "Ceren' s architecture, crafts, and agriculture were surprisingly sophisticated and varied.", he means ______.

A. Ceren at that time enjoyed a high civilization
B. people in Ceren were more intelligent than people today
Ceren' s disappearance was a tragedy
D. the power of nature was great