Answer:
I think that the answer is B. To develop plans or post-war Japan.
Explanation:
It appears to be the only one that applies to the Potsdam Conference
Oversight and public education are examples of "implied" Congressional functions, since although they are not explicitly mentioned in the Constitution, they are included in Congress's wide-reach power to regulate interstate activity.
It's the former practice of segregating black people in the US.
The right of Northerns to own slaves