Railroads encourage the growth of settlements in the west because they
a. made it easier to move products from the interior of the country to the cities
b. paid to remove local native americans making settlement safe
c. allowed police forces to travel quickly
d. paid people to settle the great plains

In the United States, railroads encouraged the growth of settlements in the west because they "A. Made it easier to move products from the interior of the country to the cities," since this meant that people who moved to the west could still make a living producing goods that were ultimately sold in the more populus regions in the east. 

He would most likely post his laws in the city market