Answer: d.) The government nationalized the railroads and created five thousand government agencies to supervise home-front activities.
Step-by-step explanation:
When the United States entered WW1 in 1917, the government knew that the only way to provide the resources needed to win the war was the centralize production so as to provide a coordinated effort across both the public and private sectors.
In light of this, the government introduced several measures such as the nationalization of the railroads. Congress also approved the creation of 5,000 temporary government agencies to help the war effort at home and provide jobs for between 500,000 to 1 million people.