What was the effect of building of new military bases as a result of world war 1?

a. training camps brought in thousands of soldiers and sailors who spent their pay locally improving the economy

b. soldiers who were stationed at training camps took jobs in the local economy, negatively affecting local residents

c. an increase in the number of camps and military bases increase the threat of military action against the area

d. with an influx of people from other parts of the nation, new ideas were introduced challenging local customs