The correct answer is A) rationing
During WWII the US government installed rationing of food, gas, and clothing. The population had to conserve their goods so it lasted longer. The government strategy was to install rationing so they could avoid shortages. This way the government sponsored some ads on radio shows and posters to urge the people to comply.
There were Red Stamp and Blue Stamp goods, each stamp authorized a purchase of goods in a certain quantity and time.