Question

roosevelts executive order no. 9066 was based on
evidence that all japanese americans were plotting to fight the us within its borders.
past experiences of japanese americans causing civil unrest in the united states.
the assumption that japanese americans posed a threat to national security.
written reports that japan was recruiting american citizens to spy for them.

Explanation:

Roosevelt's Executive Order No. 9066 during WWII was issued due to the assumption that Japanese Americans posed a national security threat (fueled by wartime hysteria and prejudice, not actual evidence of widespread plotting, civil unrest, or specific Japanese recruitment of American citizens for spying). The order led to internment of Japanese Americans.

Answer:

C. the assumption that Japanese Americans posed a threat to national security.