Competition in the mid-nineteenth century by large western farms gradually caused farmers in Pennsylvania to turn to livestock raising, but before that it was predominantly grain-producing.
B Once predominantly a grain-producing state, competition in the mid-nineteenth century from large western farms gradually was causing Pennsylvania’s farmers to turn to livestock raising.
C Pennsylvania’s farmers were gradually caused to turn to livestock raising by competition from large western farms in the mid-nineteenth century, but before that it was predominantly a grain-producing state.
D It was once predominantly grain-producing, but competition in the mid-nineteenth century by large western farms was gradually causing Pennsylvania’s farmers to turn to livestock raising.
E Pennsylvania was once a predominantly grain-producing state, but competition in the mid-nineteenth century from large western farms gradually caused the state’s farmers to turn to livestock raising.