Why does the author include the information about the "intermittent work as clockmakers, shoemakers, carpenters, and weavers" that northern cultivators engaged in? A. To suggest that northern cultivators were not as skilled at agricultural work as southern cultivators were B. To indicate an economic effect of the shorter northern growing season on northern cultivators C. To challenge the claim that work routines in the north were less intense than they were in the south D. To emphasize that northern workers tried to change their agriculturally centered economy