The correct answer is B. National security concerns over individual liberties.
Indeed, the ruling validated Executive Order 9066, ordering the internment of Japanese-Americans in security camps during WWII. The ruling deemed the executive order as constitutional.
Roosevelt did this because he feared that Japanese Americans were loyal to their ancestors and might carry out acts of sabotage and espionage.
It was found out, many years later that the Supreme Court's decision was an error since it was based on incomplete information. The government's solicitor, Charles Fahy hid a report by the Office of Naval Intelligence from the Justices. The report stated that evidence of espionage by Japanese Americans was nonexistent.
