In the Early Middle Ages, the Cultivation of New Land

In the Early Middle Ages, the cultivation of new land was hard for all of the following reasons except

A) the heavy soils of northern Europe were difficult to plow.
B) climatic changes, including colder temperatures, shortened growing seasons.
C) crude tools of the era made land clearing arduous.
D) German tribes traditionally considered trees sacred and resisted cutting them down.
E) a and c