What inspired the red scare of 1919 to 1920? was the threat real or imagined?

The Red Scare of 1919 until 1920 was inspired by the new racial violence and the seemingly antiradical hysteria that spread throughout the country. The panic created by the wartime antiradical is the peak of the Red Scare. It caused so much fear to the people though the threat is mostly imagined.

The answer is a c b d a c b d