Answer:
d. propaganda
Step-by-step explanation:
During World War One, propaganda was employed on a global scale. ... This and subsequent modern wars required propaganda to mobilise hatred against the enemy; to convince the population of the justness of the cause; to enlist the active support and cooperation of neutral countries; and to strengthen the support of allies.
Destroy this mad brute! "DESTROY THIS MAD BRUTE" is the caption of this World War I propaganda poster for enlistment in the U.S. Army. ... As a result of propaganda like this, German Americans — many of whose ancestors had lived in America for centuries — faced persecution during the war.