The reaction to September 11

a. was nonchalant as the country has been used to foreign threats.
b. was unprecedented in the history of the United States as the country was forced to respond to a new threat.
c. recalled the internment of Japanese Americans following the bombing of Pearl Harbor in 1941.
d. was the adoption of mandatory racial profiling in the United States to prevent another terrorist attack.

c. recalled the internment of Japanese Americans following the bombing of Pearl Harbor in 1941.