Answer:
The piece of evidence that supports the best the argument that Japanese American internment was not justified is that D. The U.S. government later apologized to Japanese Americans for the internment.
Explanation:
A. Option is wrong because it was not about Japanese immigrants and the attainment of U.S. citizenship. It was about the origin and the current president's order to incarcerate them for it and the risk he associated with it.
B. Option could be right, but considering they could have been connected to the attack of pearl harbor it's not enough. So, considering that only because they lived on the west coast they weren't connected to the attack, it's wrong.
C. Option doesn't explain why the internment would be unjustified.
D. Option Mentions that after some time, the U.S. government apologized for the internment. Shows that it was not justified. The research carried on, showed that everything was based on false beliefs of fear.