How did the railroads affect the relationship between eastern cities and the great plains?
a) railroads brought settlers to cities in the east and crops and grain to farms in the great plains
b) railroads brought crops and grain to cities in the east and settlers to farms in the great plains
c) railroads brought settlers west but did not bring anything east so the relationship wasn't equal
d) railroads brought crops and grain east but didn't bring anything west so the relationship was not equal