C. Many people feared the presence of Japanese spies after Japan had attacked Pearl Harbor.
Explanation:
After the Pearl Harbor attack, many Japanese American people were relocated and incarcerated in concentration camps on the west coast. The reason for this extreme measure taken by the government of the United States was that they feared that among the American citizens with Japanese ancestry there may be spies working for Japan. Around 120 000 people were interned in these concentration camps between 1942 and 1948.
