During world war ii, the event in which thousands of servicemen and civilians poured into mexican neighborhoods and assaulted mexican-americans is known as:

The answer to this is Zoot Suit Riots. In June 1943, there were a series of attacks in Los Angeles, California by white American servicemen who were then stationed in Southern California. They attacked the Mexican American youths and other minorities who lived in that city. The youths who wore zoot suits were attacked and stripped by the white servicemen and civilians because they considered the suits to be unpatriotic during the time of war because they had lot of fabric. During wartime, rationing of fabric was required. Though most of the violence was directed toward the Mexican American, young African Americans and Filipino Americans who were also wearing zoot suits were not spared in the attacks.  

number 4. should be the correct answer