“radical immigrants deported”
“bombs explode on wall street”
“palmer raids criticized by congress”
these post–world war i headlines are most
closely associated with the
(1) volstead act (3) scopes trial
(2) ku klux klan (4) red scare

I believe the answer is 4 because if you think about it, the headlines talk about "radical immigrants", "bombs exploding", and "palmer raids".  The choices given took place a while ago (i don't know of they still do :D), so if you put them together, it sounds quite a bit like the Red Scare.  :D  I hope I helped!  If you need more reasoning, just tell me!  :D