Because there was a higher concentration of Jews in Poland than almost anywhere else.
Well, technically, this is false. The Test Ban Treaty of 1963 prohibited nuclear weapons testing in the atmosphere, in outer space, and under water, but it didn't ban testing underground. However, it does prohibit nuclear explosions underground if they cause "radioactive debris" and contaminate the living surroundings.
D !! Because that’s what they went by !!
They both wanted to take over the world.